Bulletin of the American Physical Society
17th Biennial International Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 56, Number 6
Sunday–Friday, June 26–July 1 2011; Chicago, Illinois
Session F1: Poster Session (5:30 - 7:30pm) |
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Chair: Nicola Bonora, University of Cassini, Italy, and Eric Herbold, Lawrence Livermore National Laboratory Room: Grand Ballroom I-III |
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F1.00001: BALLISTICS STUDIES |
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F1.00002: Ultrafine particle size distribution during high velocity impact of high density metals Giorgio Buonanno, Luca Stabile, Andrew Ruggiero, Gianluca Iannitti, Nicola Bonora In the event of kinetic energy penetrator impact, survival personnel is exposed to the additional hazard stemming from ultrafine metallic particles, i.e. exposure, inhalation, and respiration of aerolized metals. Aerosol particle size distribution is an important parameter that influences aerosol transport and deposition processes. In order to have reliable quantitative measure of the aerosol particles generated under controlled impact conditions, an experimental set-up has been developed. Both non penetrating and penetrating impacts tests have been designed and performed with light gas-gun in chamber. During the impact, size distribution, total concentration and chemical composition of ultrafine particles have been measured and correlated with impact parameters (such as energy and velocity). In order to avoid measurement contamination, as a result of undesired participating materials, target and projectile have been made of the same metal and tests have been performed in clean environmental chamber. In this study the results relative to high purity copper are presented. [Preview Abstract] |
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F1.00003: Two-dimensional Imaging Velocity Interferometry of laser shock driven Si Raymond Smith, Cynthia Bolme, David Erskine, Peter Celliers, Jon Eggert, Gilbert Collins We present results of 1D and 2D velocimetry measurements of shock compressed Si conducted on the Janus laser facility at the Lawrence Livermore National Laboratory. A 6ns long laser pulse ablatively shock compresses a 300 micron thick Si [111] single crystal sample. A standard 1D line VISAR technique is then used to record the Si/vaccum or Si/LiF interface velocity histories. Concurrently a 2D velocity interferometry technique records the spatial structure of the deformation at one time during the compression. The 2D interferometer offers 2-micron spatial resolution and $\sim $10 m/s velocity resolution. Our data show very different spatial and velocity structures with deformation associated with elastic-, plastic- and high pressure phase deformation. The presence of a LiF window is shown to suppress velocity jetting consistent with fracture from the free-surface samples. The data from the high resolution 2D interferometer reveals a richness in surface morphology only hinted at with standard spatially integrating VISAR techniques. [Preview Abstract] |
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F1.00004: Scaled Long Rod Perforation Experiments Using Multiple Diagnostics Daniel Cross, William Proud A series of angled small-scale reverse ballistic long rod experiments were conducted using mild steel rods (6 mm dia., 90 mm long) against both 3 mm and 6 mm rolled homogeneous armour (RHA) plates at 30$^{\circ}$. The impact velocity was varied from 450-780 m s$^{-1}$ and the response of the system monitored by laser velocimetry, strain gauges and high-speed photography. This provided insight into the flexing of the rod during impact, the acceleration of the rear of the rod and the global penetration process. This experimental series involved ricochet, near-ricochet and full perforation, and so allows the sensitivity of the differing diagnostic outputs for these processes to be compared. [Preview Abstract] |
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F1.00005: Experimental and Numerical Investigation on the Ballistic Resistance of Double-Layered Steel Plates Xinke Xiao, Wei Zhang, Zitao Guo, Gang Wei The ballistic perforation resistance of double-layered steel plates impacted by flat-nosed projectiles was investigated both experimentally and numerically. In the tests, 10 mm thick (intact or spaced by 200 mm gap space) targets of Q235A steel were impacted using a gas-gun at sub-ordnance velocity, and the ballistic limit velocity of the different target configurations was obtained. The Johnson-Cook strength and fracture models were used in the finite element simulations, where the model constants were calibrated by preliminary material tests and taken from open literature. In general, good agreement was obtained between the numerical simulations and the experimental results. It was found that the ballistic resistance of spaced targets suffers from large divergence due to the projectile's different residual attitude after perforation of the front plate, and that it seems the initial-residual velocity data yield to two groups and therefore give birth to two ballistic limit velocities. However, the overall ballistic resistance of the spaced targets is less than that of the in contact ones. [Preview Abstract] |
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F1.00006: Experimental and Numerical Study of Water-Filled Vessel Impacted by Flat Projectiles Peng Ren, Wei Zhang, ZiTao Guo, Gang Wei To understand the failure patterns and impact resistance of watertight vessel, a flat-nosed projectile was accelerated by a two--stage light gas gun against a vessel filled with water which was placed in an air-filled tank. The targets were the 5A06 aluminum which were installed on two opposite sides of the vessel. The penetration process was recorded by a digital high-speed camera. In order to compare, numerical simulations for the vessel with and without water impacted by projectiles were conducted by AUTODYN-3D. The material parameters of targets and projectiles used in the simulation were obtained from several previous studies. The result indicated that experimental and numerical results were in good agreement. Numerical simulations were capable to capture the main physical behavior. It was also found that the impact resistance of targets in the water-filled vessel was lager than that of the empty vessel. Tearing was the main failure models of the water-filled vessel targets which was different from that of the empty vessel where the shear plugging was in dominate. [Preview Abstract] |
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F1.00007: The Formation and Stretching of Bi-material Shaped Charge Jets John Curtis, Frank Smith, Alex White The equations for the formation of a bi-material jet from a laminated shaped charge liner are presented. A coupled pair of boundary-value problems is then established for an idealised stretching jet in cases where the outer material occupies a hollow uniform cylinder surrounding the inner material in the uniform hollow. This is done first where the materials are inviscid fluids. Making the assumption that the axial velocity in each part of the jet is the same and linearly decreasing from the front to the rear of the composite jet, solutions for the pressure field in each part are obtained. The problem is then reformulated where the two materials are both perfectly plastic solids but with differing densities and yield strengths. The equations of plastic flow (Levy-Mises with von-Mises yield criterion) are solved for each material to derive the stress field in both parts of the jet. These analytical solutions offer a basis for future stability and target penetration studies. [Preview Abstract] |
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F1.00008: Equation of State for a Mixture of Unreacted HE and HE Detonation Products B.A. Nadykto For most of explosive conversion kinetics simulations associated with the analysis of HE initiation, one needs to know equations of state (EOS) of yet unreacted (``cold'') HE and a mixture of cold HE and detonation products (DP). Earlier, we have developed EOS of HE and DP using the same (universal) analytical form of EOS. EOS parameters are fitted based on the comparison with experiment. In detonation products, rather large HE molecules are divided into small fragments, with H$_{2}$O and CO$_{2}$ constituting the larger fraction of them. Therefore, the equilibrium density of DP at T=0 in the simulations is assumed to be equal to about 1.2 g/cm$^{3}$. In fact, EOS parameters for DP are chosen such as to describe the largest possible set of experimental data, including the Jouget point parameters for different HE densities, unloading isentropes from the Jouget point, parameters of overdriven detonation and DP recompression (DP deceleration curve). We propose an EOS of the same form for a mixture of cold HE and DP. The equilibrium density of the mixture (at P=0, T=0) is defined as 1/$\rho ^{0}_{mix}=\alpha $/$\rho ^{0}_{DP}$ + (1--$\alpha )$/$\rho ^{0}_{HE}$. The bulk compression modulus is calculated as B$^{0}_{mix}$ = B$^{0}_{HE }$(1--$\alpha +\alpha \rho ^{0}_{HE}$/ $\rho ^{0}_{DP})$/(1--$\alpha +\alpha \rho ^{0}_{HE}$B$^{0}_{HE}$ /$\rho ^{0}_{DP}$ B$^{0}_{DP})$. Here, $\alpha $ is the DP mass fraction in the mixture. Such formulas give an adequate transition to the EOS of pure mixture components. [Preview Abstract] |
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F1.00009: BIOLOGICAL/NANOMATERIALS |
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F1.00010: On the shock response of Pisum Sativum (a.k.a the Common Pea) James Leighs, Paul Hazell, Gareth Appleby-Thomas The high strain-rate response of biological and organic structures is of interest to numerous fields ranging from the food industry (dynamic pasteurisation) to astrobiology (e.g. the theory of panspermia, which suggests that planets could be `seeded' with life `piggy-backing' of interplanetary bodies). Consequently, knowledge of the damage mechanisms and viability of shocked organic material is of paramount importance. In this study a single-stage gas-gun has been employed to subject samples of Pisum Sativum (the Common Pea) to semi-planar shock loading, corresponding to impact pressures of up to c.3 GPa. The experimental approach adopted is discussed along with results from Manganin gauges embedded in the target capsule which show the loading history. Further, the viability of the shock-loaded peas was investigated via attempts at germination. Finally, microscopic examination of the impacted specimens allowed a qualitative assessment of damage mechanisms to be made. [Preview Abstract] |
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F1.00011: ABSTRACT WITHDRAWN |
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F1.00012: Cellular characterization of compression induced-damage in live biological samples Chiara Bo, Jens Balzer, Mark Hahnel, Sara M. Rankin, Katherine A. Brown, William G. Proud Understanding the dysfunctions that high-intensity compression waves induce in human tissues is critical to impact on acute-phase treatments and requires the development of experimental models of traumatic damage in biological samples. In this study we have developed an experimental system to directly assess the impact of dynamic loading conditions on cellular function at the molecular level. Here we present a confinement chamber designed to subject live cell cultures in liquid environment to compression waves in the range of tens of MPa using a split Hopkinson pressure bars system. Recording the loading history and collecting the samples post-impact without external contamination allow the definition of parameters such as pressure and duration of the stimulus that can be related to the cellular damage. The compression experiments are conducted on Mesenchymal Stem Cells from BALB/c mice and the damage analysis are compared to two control groups. Changes in Stem cell viability, phenotype and function are assessed flow cytometry and with in vitro bioassays at two different time points. Identifying the cellular and molecular mechanisms underlying the damage caused by dynamic loading in live biological samples could enable the development of new treatments for traumatic injuries. [Preview Abstract] |
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F1.00013: COMPOSITES AND POLYMERS |
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F1.00014: High Strain Rate Mechanical Properties of Glassy Polymers Jennifer Jordan, Clive Siviour, Brian Woodworth Since the early 1990s, a range of experimental data has been generated describing the response of glassy polymers to high strain rate loading \textit{in compression}. More recently, research programs that study the combined effects of temperature and strain rate have made significant steps in providing better understanding of the physics behind the observed response, and also in modeling this response. However, limited data are available in tension, and even more limited are data describing both the compressive and tensile response of the same polymer. This paper investigates the compressive and tensile response of four glassy polymers across a range of stain rates from quasi-static to dynamic. The pressure dependant yield in these materials will be discussed through comparison of the tensile and compressive yield stresses. [Preview Abstract] |
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F1.00015: DETONATIONS AND SHOCK-INDUCED CHEMISTRY |
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F1.00016: A Reaction Rate Model for Detonation of PBX-9502 Jun Chen People always try to make macroscopic phenomenological reaction rate model to simulate detonation phenomenon. But these models have the limitation whose model parameters are different with those got by experiments. In this paper, a simple reaction rate model of PBX-9502 has been proposed using Lagrange analysis method for high explosives. With this model, longitudinal structure of reaction zone of PBX-9502 was obtained. Then the results of our model are compared with ignition {\&}growth model. From the analyzing the detonation reaction rate with pressure (p) and reaction fraction of mass ($\lambda$), we describe the reaction rate equation of PBX-9502 detonation process. We use nonlinear optimization method to get the parameters (z, x, G) of the above-mentioned reaction rate equation. Coupling this equation into DYNA2D, we simulate the shock initiation process that one centimeter Kel-F impacts PBX-9502 at a speed of 3970m/s. We also compare our results with the ignition{\&}growth model. These two models can describe the detonation reaction zone very well. [Preview Abstract] |
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F1.00017: Theoretical study of the influence of the equation of state mixture properties on the velocity-curvature relationship for heterogeneous solid explosives Christophe Matignon, Nicolas Desbiens, Remy Sorin, Vincent Dubois DSD is probably the most popular engineering tool used to model the dynamics of detonation. In this model the normal shock velocity (Dn) depends only on the local curvature (k) of the front. One way to reproduce this behavior is to construct a model for the explosive which obeys the 1D quasi-steady weakly curved detonation theory$^{1}$. In its simplest form, such a model is composed of a reactive equation of state (ideal mixture of a burnt unburnt phases) coupled with a single step burning law. To complete the description of the reactive EOS different authors$^{2,3}$ proposed various closure hypotheses (isobaric isothermal, isobaric adiabatic, isodensity isothermal,{\ldots}). Given this form of the EOS, the rate law is then calibrated to match the experimental detonation velocity-curvature curve. In this paper we theoretically examine the influence of the EOS closure hypotheses on the (Dn,k) curve. As the 1D curved theory of detonation is extremely sensitive to the calculation of the sonic surface downstream the reaction zone, we show that the effect of a particular closure law for the mixture can have a dramatic effect whenever it alters the sound speed calculation at the end of the reaction zone. $^{1}$Stewart et al., Comb. Institute, 2000 $^{2}$Wescott et al., JAP, 2005 $^{3}$Matignon et al., 14th Int. Symp. Det., 2010 [Preview Abstract] |
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F1.00018: Application of Proton Radiography to Detonation Wave Propagation - a ``Sandwich Test'' Maria Rightley Proton Radiography (often referred to as pRad) was invented at Los Alamos National Laboratory and has been operational for many years at the Prad Facility as part of the Los Alamos Neutron Science Center. Early in its history, it was realized that this diagnostic was very well suited to visualizing evolving detonation front(s). In this presentation, we concentrate specifically on one configuration that has been radiographed at the pRad facility. A block of PBX 9501 is ``sandwiched'' between two plates of steel and initiated by line wave generators at each end. With the multiple frame capability of pRad (20+ frames), the propagation of the detonation wave over several microseconds is captured. The experimental configuration, some details of the pRad facility, and the results will be discussed in this presentation. [Preview Abstract] |
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F1.00019: The Characteristic of Porous Charges on a Base of a Water-Filled RDX Powder Georgy Valiano, Boris Yankovskiy, Vladimir Milyavskiy, Tatiana Borodina A detonation velocity of a condensed RDX linearly depends on density at a range of 1,0-1,8 g/c$m^3$. These charges are porous if the density of RDX monocrystal is 1,806 g/c$m^3$. The state of porous charge can be characterized by the packing density. It can be rising, if RDX powder will be mixed with water for deciding technological problems. It is necessary to be able to predict characteristics of such charges. Charges on a base of a water-filled RDX powder with air inclusions can be described by three parameters: a density of a charge, packing density of RDX powder and RDX mass fraction. Last two parameters are independent parameters of a mix. We have designed a nomogram for definition of mutual communication of three quantities: velocity of a detonation, density of packing of RDX powder and its mass fraction in a mix. To check up correctness of a prelegends of a nomogram, we have carried out measurement of a detonation velocity of porous water-contained RDX charges. We prepared charges on a base of RDX powder which has consisted of particles with a size 80-220 mcm. We was changing RDX mass fraction of charges in a range 0,6-1,0 and a packing density of RDX powder in a range of 1,0-1,4 g/c$m^3$. The disorder of experimental data concerning the nomogram data did not exceed basically of 3 percent. [Preview Abstract] |
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F1.00020: Conditions of Experimental Realization of an Electric Detonation Boris Yankovskiy The detonation can be subdivided on chemical one, light one (laser breakdown of gases), electronic one (electric breakdown in solid dielectric from the anode) depending on an energy source. The electric detonation is the chemical detonation with additional energy release in a chemical reaction zone as result of heating from the going electric current. The chemical reaction zone has some thickness and appreciable conductivity. The required effect of an expected electric detonation can be the increase of detonation velocity D related to dimensionless ratio: $(D_2/D_1)^2\sim W_2/W_1$. $W_1$ is a density of the released chemical energy (J/$m^3$), $W_2$ is total density chemical and thermal energy by an external electric source allocated in chemical reaction zone (J/$m^3$). The pulse electric source should provide density of a flow and specific allocation of energy, corresponding to similar quantities of the chemical nature in a zone of chemical reaction. We analyzed a detonation of disk-shaped assemblage with diameter 20 cm and weight of HE charge about 0,5 kg. The analysis has shown, that the pulse source is necessary for guaranteed realization of an electric detonation with an energy capacity 5 MJ and which can make a current from 0,4 up to 13 MA on prospective load 0,016-0,16 Ohm. We have accepted efficiency of energy transfer at level of 50 percent. The effect of increase of a detonation velocity can make 15-30 percent. [Preview Abstract] |
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F1.00021: Shock Initiation and Detonation Properties of Bis-fluorodinitroethyl formal (FEFO) L.L. Gibson, S.A. Sheffield, D.M. Dattelbaum, D.B. Stahl, R. Engelke FEFO is a liquid explosive with a density of 1.6 g/cm$^{3}$ and an energy output somewhat higher than trinitrotoluene (TNT), making it one of the more energetic liquid explosives. Shock initiation experiments were conducted on a two-stage, gas gun using magnetic gauges to measure the wave profiles during a shock-to-detonation transition. Both unreacted Hugoniot data, as well as run-to-detonation measurements were obtained, along with the reactive wave profiles. FEFO was found to initiate by the homogeneous initiation model, as do all other liquid explosives we have studied. The new unreacted Hugoniot points agree with other published data and a universal liquid Hugoniot estimates the Hugoniot data quite well. It is quite insensitive, with about the same shock sensitivity as the triamino-trinitro-benzene-based explosives PBX9502 and LX-17. In addition to the shock initiation experiments, one experiment was done on the gun providing a reasonably accurate detonation velocity and a detonation wave profile. These are compared to the waveforms from the in-situ magnetic gauges, as well as to other data available in the literature. [Preview Abstract] |
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F1.00022: Towards the role of interfacial shear in shock-induced intermetallic reactions Mark Collinson, David Chapman, David Williamson, Mark Burchell, Daniel Eakins Shock-induced intermetallic reactions have previously been shown to occur on a nanosecond timescale, within the rise time of the applied shock wave. Work in this area to date has however concentrated on continuum scale measurements, raising questions as to the processes occurring at micro and meso scales. Mass transfer due to inter-facial shear at material interfaces has been suggested as a possible explanation. We will present initial work examining the role of friction on this mass mixing process across a binary interface. This work includes plate impact experiments on an inert stainless steel -- aluminum friction pair, employing spatially resolved interferometry. Results from a series of metal ball-on-angled plate impact experiments at 1-2 km/s will also be presented, supported by high-speed imaging and target recovery. [Preview Abstract] |
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F1.00023: Numerical Model of Detonation for Insensitive HE Vladimir Klimenko Most of modern munitions are filled by insensitive HE. However, mechanism of initiation of these HE is still unknown. IHE have not any pores and, therefore, hot spot mechanism does not work here. What is a mechanism working in this case? We have used 3D hydrocode to study process of shock wave loading of mixture of HMX grains with different binders (HMX/binder=88/12) and have determined formation of surface layers with increased plastic deformation. According to the dislocation mechanism of detonation (V. Klimenko, I. Kozyreva, J. Energetic Materials, 2010, v. 28, pp. 249-262) plastic deformation generates definite concentration of radicals. Surface layers have also increased temperature due to viscous work. So, these activated layers have increased temperature and number of radicals in comparison with values inside grains. Kinetic calculation has shown fast decomposition of these layers. As a result, the activated layer is ignited and this gives beginning of grain burning process. The developed two-stages mechanism has been incorporated into 2D hydrocode. The developed numerical model demonstrates high accuracy in simulation of detonation processes in IHE (in particular, PBXN-110 and B2241). [Preview Abstract] |
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F1.00024: Simulation of attenuation regularity of detonation wave in PMMA Wei Lan, Hu Xiaomian Polymethyl methacrylate (PMMA) is often used as clapboard or protective medium in the parameter measurement of detonation wave propagation, due to its similar shock impedance with the explosive. Theoretical and experimental research show that the pressure of shock wave in condensed material has the regularity of exponential attenuation with the distance of propagation. Simulation of detonation wave propagation in PMMA is conducted using a two-dimensional Lagrangian computational fluid dynamics program, and results are compared with the experimental data. Different charge diameters and different angles between the direction of detonation wave propagation and the normal direction of confined boundary are considered during the calculation. Results show that the detonation wave propagation in PMMA accords with the exponential regularity of shock wave attenuation in condensed material, and several factors are relevant to the attenuation coefficient, such as charge diameter and interface angle. [Preview Abstract] |
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F1.00025: Sporicidal Effects of Iodine-oxide Thermite Reaction Products Rod Russell, Stephan Bless, Alexandra Blinkova, Tiffany Chen Iodine pentoxide-aluminum thermite reactions have been driven by impacts at 1000 m/s on steel plates 3 mm or thicker. The activation energy of this material reaction is 197 J/g. The reactivity is increased by reducing grain size. This reaction releases iodine gas that is known to be a sporicide. In order to test the impact reactions for sporicidal effects, reactions took place in closed chambers containing dried \textit{Bacillus subtilis} spores. The reduction in colony-forming units was dependent on the exposure time; long exposure times resulted in a 10$^{5}$ decrease in germination rate. This was shown to be due to the gas exposure and not the heat or turbulence. Sporicidal effectiveness was increased by adding neodymium and saran resin. The sporicidal effect is very dependent on exposure time, ranging from about 90{\%} kill for times on the order of a second to 99.99{\%} for one-hour times. [Preview Abstract] |
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F1.00026: 3D DSD Calculation in a Rectangular Bar by the Direct Algorithm Yehuda Partom According to detonation shock dynamics (DSD), the normal front velocity at any point on a detonation front is D$_{n}$(k), where k is the local mean curvature. In rectangular coordinates a point on the front therefore moves according to: dx/dt=D$_{n}$cos(n,x), dy/dt=D$_{n}$cos(n,y) and dz/dt=D$_{n}$cos(n,z). The direct DSD algorithm makes use of these simple equations. We define the detonation surface by putting discrete points on it as densely as needed. At each point we have the above three ODEs. For m such points we therefore have a system of 3m ODEs. We propagate the front by solving them simultaneously, where we calculate the mean curvature k by a finite difference approximation. At the boundaries we apply the limiting angle constraint. In the paper we demonstrate the use of the direct algorithm for a special relatively easy case of detonation in a bar with a rectangular cross section, with different values of a/b. We compute the size effect curves and compare with the diameter effect curve of a circular bar of the same cross section area. [Preview Abstract] |
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F1.00027: The AMRDEC Process for Analyzing Initiation Effectiveness Against Explosive Filled Small Arms Threats Dedra Moore The mortar threats, due to their small size and robust structure, present difficult challenges to new and existing systems for acquisition, tracking, intercept and defeat. Defeat must come through either the fuze or detonation of the explosive. Direct detonation of the explosive payload at the point of intercept via fragment or direct missile impact is considered a more achievable alternative. A pre-detonation of the fuze due to impact can produce similar results. However, fuzes can be a small percentage of the target area. Another possible outcome is the fuze would simply be duded. However, a dudded mortar can be indistinguishable from a non-dudded mortar until it strikes the ground. A robust process must have the capability of analyzing multiple solution types. An extensive database of single fragment impacts against threats with high explosive payloads was utilized to develop and modify models to predict explosive reaction. The goal was to create models or equations that could be incorporated into fast running simulation tools to access potential lethal mechanisms over a wide range of battlespace conditions quickly. A methodology to ascertain impact effectiveness on a typical generic threat fuze was also developed separately to be included in the simulation tools. Computational efforts and trade studies can be conducted with fast running simulation tools whose accuracy had been validated with significant test data. [Preview Abstract] |
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F1.00028: EXPERIMENTAL DEVELOPMENTS |
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F1.00029: Recovering a Short Timescale Signal from a Pair of Long-delay VISARs David Erskine In the traditional use of a velocity interferometer system (VISAR) the detector is slow compared to the interferometer delay and there is no short timescale signal portion in the record. In this case the VISAR acts in a ``derivative'' mode to target displacement and the velocity output is treated as proportional to the fringe phase. With modern detectors however, one can now measure signals as fast or faster than the interferometer delay. The VISAR behaves in a ``difference'' mode (which is the more fundamental mode), and the velocity is no longer simply proportional to the fringe phase-- a different mathematics for extracting the signal is required, which we have explored. We find that rather than use iterative equations, it is more fruitful to model the VISAR as a linear filter and analyze in the Fourier domain. In particular, by simultaneously using two VISARs with different delays, we demonstrate on simulated data that we can accurately recover the short timescale behavior of a target, shorter than the interferometer delay. [Preview Abstract] |
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F1.00030: Experimental Technique for Direct Observation of Onset of Reaction in Shocked Powder Mixtures Fran\c{c}ois-Xavier Jett\'e, Sam Goroshin, Andrew Higgins, David Frost, Julian Lee A new experimental technique was developed to directly observe the onset of shock initiation in powder mixtures contained in recovery capsules over time scales ranging from hundreds of nanoseconds to at least hundreds of milliseconds. Simultaneously with a thermocouple embedded in the test mixture to monitor bulk temperature changes, a photomultiplier tube detected light emissions produced by the reacting sample. A particular window/optic fiber system was developed that remained intact and did not move during the experiment. A T-shaped polycarbonate window was placed into a steel recovery capsule, which was held solidly in place in a heavy steel anvil designed to protect the fiber optic and to prevent motion of the polycarbonate window. Samples of as-blended 5Ti+3Si powders and ball-milled mixtures 5Ti+3Si were tested in this setup. In all experiments, a weak light emission peak was observed upon shock passage followed by much more intense light emissions beginning a few milliseconds to a few hundreds of milliseconds later. The intense light emissions occurred at approximately the same time as a bulk temperature increase measured with the thermocouple. These results suggest that only a very small fraction of the sample was initiated by the shock. This setup shows promise for further studies of shock initiation in reactive powders. [Preview Abstract] |
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F1.00031: On the Development of a Modified Wedge Test for Shock-to-Detonation Transition in Explosives Using ORVIS Marcia Cooper, Wayne Trott Experiments using a wedge-shaped explosive sample shocked with an attenuator-explosive booster are historically used to provide data for fitting an empirical relationship between the known input stress and shock-to-detonation run distance. Recent problems with plane wave lens availability and increased needs for characterizing novel explosive formulations have highlighted the need for a modernized approach to transitional wedge tests. We present our concept of a modified wedge test which uses a gas gun, and explosive wedge sample and the line-imaging ORVIS (optically recording velocity interferometer system) diagnostic. The ORVIS optical configuration is modified from the standard configuration to project the laser line onto the inclined surface of the explosive sample where the return light is collected with a streak camera. Initial data of shock breakout in inert and explosive samples is presented and discussed. [Preview Abstract] |
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F1.00032: Measurement of Impact Surface with a Frontal Electrode Ilan Be'ery, Moshe Aharon Laboratory guns are a major tool in the measurements of shock. When high precision is required, the tilt and bow of the impactor must be measured. This is usually done with an array of shock-arrival diagnostics at the back of the target. Such an array limits the useful surface area and thickness of the target. In the present work we demonstrate that the tilt and bow can be measured by using a thin electrode with many shorting strips, which is attached to the front surface of the target. The exact location of the shorting point in each strip is not predetermined, but depends on the impactor's tilt and bow. Nevertheless, in most cases the entire shorting sequence can be fitted with high confidence and accuracy to a unique combination of tilt and bow. The accuracy of tilt and bow measurements with this electrode are comparable to those obtained with shorting pins at the back of the target. [Preview Abstract] |
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F1.00033: Quartz as an impedance-matching standard for shock studies Amy Lazicki, Jon Eggert, Ryan Rygg, Damien Hicks, Gilbert Collins Alpha-quartz has been developed and frequently used as a convenient standard for impedance-matching in shock studies. Recent results have revealed differences in the Hugoniot of quartz measured using laser-driven vs. plate-impact methods. The choice of standard in many cases has a significant impact on experimental results. We present a thorough investigation of the implications of this difference in quartz standard for the existing experimental reports, with recommendations for future studies. [Preview Abstract] |
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F1.00034: Techniques for measuring ultrahigh-pressure Hugoniot equation of state on a three-stage gas gun Xiang Wang, Jianbo Hu, Chengda Dai, Qiangsong Wang, Jingsong Bo, Hua Tan, Yuying Yu A three-stage gas gun was developed by mounting an extending launcher tube on a two-stage gas gun, and was successfully applied to perform ultrahigh-pressure Hugoniot measurements for Ta and Pt by using this three-stage gun. Here we introduced the three-stag gas gun launcher and Hugoniot measurement techniques, including shock front shape diagnosis, shock wave velocity and impact velocity measurement as well as numerical simulation. By using this three-stage gun, Ta or Pt impactors were launched up to $\sim $10 km/s, and the Hugoniot data were respectively measured with high accuracy up to 750 GPa for Ta and 1TPa for Pt. It is demonstrated that the three-stage gas gun is a promising technique for studying the ultrahigh-pressure properties of materials, which never before obtained by utilizing two-stage light-gas-gun. [Preview Abstract] |
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F1.00035: Temperature Control for the VELOCE Electromagnetic Driver A.W. Shay, J.J. Lynch, D.G. Dalton, R.J. Hickman, M.D. Willis, A.J. Lopez, J.L. Wise, S. Root Sandia's VELOCE pulsed-power generator has been used extensively to perform shockless compression experiments on various materials. Preheating and precooling (i.e., cryogenic) systems have now been developed for VELOCE that allow control of the initial sample temperature, thereby dramatically expanding the range of achievable thermodynamic end states. The designs and capabilities of these systems are described, along with their application to dynamic material testing (e.g., equation-of-state, phase transition, and strength studies). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U. S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. [Preview Abstract] |
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F1.00036: High pressure Hugoniot measurements using Mach waves Justin Brown, Guruswami Ravichandran In an effort to dramatically increase the range of pressures which can be accessed by traditional shock loading methods, a composite target assembly is examined. The target consists of two concentric cylinders aligned with the axial direction parallel to the loading, and is designed such that the outer cylinder will initially have a higher shock velocity than the inner material of interest. Conically converging shocks will be generated at the interface between the two materials due to the impedance mismatch. Upon convergence, an irregular reflection occurs and the conical analog of a Mach reflection develops. The Mach reflection will grow until it reaches a steady state, at which point the wave configuration becomes self similar. The resulting high pressure Hugoniot state can then be measured using velocity interferometry and impedance matching. The technique is demonstrated using a planar mechanical impact generated by a powder gun to study the shock response of copper. Two systems are examined which utilize either a low impedance (6061-T6 aluminum) or a high impedance (molybdenum) outer cylinder. A dual-delay multipoint VISAR experiment will be presented to validate the technique, and will be compared to both numerical simulations and a simple hydrodynamic model. The feasibility of measuring an entire Hugoniot curve using full field velocity interferometry (ORVIS) will also be discussed, and initial experiments will be presented. [Preview Abstract] |
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F1.00037: Design and identification of high performance steel alloys for structures subjected to underwater impulsive loading Xiaoding Wei, Felix Latourte, Zack Feinberg, Gregory Olson, Horacio Espinosa To characterize the performance of naval structures, underwater blast experiments have been developed. Martensitic and austenitic steel alloys were designed to optimize the performance of structures subjected to impulsive loads. The deformation and fracture characteristics of the designed steel alloys were investigated experimentally and computationally. The experiments were based on an instrumented fluid structure interaction apparatus, in which deflection profiles were recorded. The computational study was based on a modified Gurson damage model able to accurately describe ductile failure under various loading paths. The model was calibrated for two high performance martensitic steels (HSLA-100 and BA-160) and an austenitic steel (TRIP-120). The martensitic steel (BA-160) was designed to maximize strength and fracture toughness while the austenitic steel (TRIP-120) was designed to maximize uniform ductility. The combined experimental-computational approach provided insight into the relationships between material properties and blast resistance of structures. [Preview Abstract] |
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F1.00038: Implosion-driven technique to create fast shock waves in high-density gas Matthew Serge, Daniel Szirti, Jason Loiseau, Andrew Higgins, Vincent Tanguay The ability of an explosively clad tube to drive high velocity ($>$ 8 km/s), quasi-steady shock waves through a high pressure ($>$ 10 MPa) gas filling the tube is investigated. The experimental device consists of a thin-walled tube filled with high-pressure helium and then surrounded by a layer of explosive in turn surrounded by a thick-walled tamper. Implosion causes the inner tube to pinch, forming a shock wave that moves into the gas faster than the detonation wave. The limitation of the device is the dynamic yielding and failure of the tube containing the gas. Multiple geometries are explored, which vary the thickness and number of explosive layers. The incorporation of secondary steel cylinders in the explosive layer to act as a dynamic tamper is also investigated. A simple model for the radial, one-dimensional dynamics of the apparatus was developed to predict the relative success of the varying geometries, as measured by the relative difference in shock velocity and stand-off distance as compared to the detonation in the explosive. This technique can be coupled with phase-velocity generating devices (explosive lenses) to drive high-density shock waves to arbitrarily high velocities ($>$ 15 km/s). In addition to being used to create states of high-energy density, this technique can be applied to an implosion-driven hypervelocity launcher for projectiles. [Preview Abstract] |
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F1.00039: ABSTRACT HAS BEEN MOVED TO Y2.00002 |
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F1.00040: Increasing Data from High Rate Characterization Experiments using Optical Reconstruction Clive Siviour, Matthew Arthington, Euan Wielewski, Nik Petrinic Uniaxial characterization experiments in tension and compression are widely used to evaluate the mechanical response of materials to applied deformation over a wide range of strain rates. For many materials, specimens with initially circular cross sections will evolve to become elliptical. There is an opportunity to more fully characterize such materials by reconstructing the elliptical shape during the deformation process. This also allows us to better evaluate the stress and strain in the specimen during deformation. We have developed a technique whereby images of a specimen during deformation (for example, from a high speed camera) from three different angles are used to reconstruct its cross section during an experiment. The technique has been applied to tensile Hopkinson bar experiments and Taylor Impact experiments on hcp materials. This paper presents an overview of the technique and the data that it can provide. [Preview Abstract] |
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F1.00041: Index of Refraction Measurements and Window Corrections for PMMA under Shock Compression David Chapman, Daniel Eakins, David Williamson, William Proud Symmetric plate impact experiments were performed to investigate the change in the refractive index of PMMA under shock loading. Flyer and target geometries allowed the measurement of shock velocity, particle velocity, and refractive index in the shocked state, using the simultaneous application of VISAR (532nm) and Het-V (1550nm). The change in refractive index of PMMA as a function of density is generally considered to be well described by the Gladstone-Dale relationship, meaning that the ``apparent'' velocity measured by a laser velocity interferometer is the ``true'' velocity, and hence there is no window correction. The results presented characterise the accuracy of this assumption at peak stresses up to 2 GPa. [Preview Abstract] |
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F1.00042: High-precision study of friction between stainless steel and aluminium alloy Ronald Winter, Stewart Stirk, Mark Collinson We have studied dynamic friction by using an impacting copper plate to drive a tapered aluminium alloy plug into a matching hole in a stainless steel outer sheath. The velocity of the back surface of the plug was measured using velocity interferometry. Unfortunately it was found that apparently identical configurations gave significantly different velocity profiles. This was taken as an indication that friction was very sensitive to the preparation or assembly of the components. Therefore a series of experiments were conducted in which the manufacturing tolerances were tightened and the assembly procedure was more carefully controlled than previously. Five experiments have been performed at the same impact velocity, (300m/s). Comparing the recent results with those fired previously it is clear that the results form three distinct groups which are different from each other, but within which the results are highly reproducible. Previous work suggested that melting of a thin layer of aluminium at the rubbing interface, an inherently unstable phenomenon, may be controlling the behaviour of the assembly. This contention is supported by post-shot metallography of the aluminium cones recovered from the latest batch of experiments [Preview Abstract] |
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F1.00043: Phase velocity enhancement of linear explosive shock tubes Jason Loiseau, Matthew Serge, Daniel Szirti, Andrew Higgins, Vincent Tanguay Strong, high density shocks can be generated by sequentially detonating a hollow cylinder of explosives surrounding a thin-walled, pressurized tube. Implosion of the tube results in a pinch that travels at the detonation velocity of the explosive and acts like a piston to drive a shock into the gas ahead of it. In order to increase the maximum shock velocities that can be obtained, a phase velocity generator can be used to drag an oblique detonation wave along the gas tube at a velocity much higher than the base detonation velocity of the explosive. Since yielding and failure of the gas tube is the primary limitation of these devices, it is desirable to retain the dynamic confinement effects of a heavy-walled tamper without interfering with operation of the phase velocity generator. This was accomplished by cutting a slit into the tamper and introducing a phased detonation wave such that it asymmetrically wraps around the gas tube. This type of configuration has been previously experimentally verified to produce very strong shocks but the post-shock pressure and shock velocity limits have not been investigated. This study measured the shock trajectory for various fill pressures and phase velocities to ascertain the limiting effects of tube yield, detonation obliquity and pinch aspect ratio. [Preview Abstract] |
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F1.00044: The reverse edge-on impact test: a small scale experiment to study non-shock ignition Didier Picart, David Damiani, Michel Doucet Low velocity impact response of HMX-based high explosives is still a challenging domain for researchers and engineers. Studies are focused on the characterization of mechanical behavior and the determination of accurate dynamic mechanical constitutive laws, the numerical simulation of highly localized fields and the determination of the hot-spot formation mechanism. This last topic mixes phenomenological assumptions at the microstructural level, about the dissipation mechanism (cristal plasticity and/or friction of micro cracks lips), to more or less empirical rules relating the macroscopic mechanical quantities to the fields of stress, strain and strain rate at the microstructural level. To contribute to this study, the punch test apllied in 1998 by the Los Alamos team to a high explosive has been revisited. A reversed edge-on impact test has been designed. It enables real-time recordings of ignition at the macroscopic level, post-mortem observations as well as numerical simulation at the mesoscale. The talk will give details about the experimental set-up, the main results obtained for various impact conditions and a first attempt to simulate the heterogeneous pressure and strain rate at the mesoscale. [Preview Abstract] |
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F1.00045: Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction Dane Morgan Recent advances in pulsed x-ray diffraction (XRD) diagnostic techniques have enabled real-time XRD studies of atomic-scale mechanisms within shocked polycrystalline materials. The direct correlation between solid-state structures and their associated XRD patterns enables direct observation of a material's bulk properties, including phase, grain-size distribution, texture, and micro-strain, during the very short time interval of shock-induced pressure loading. For shock-compressed polycrystalline solids, real time single-pulse XRD probes a macroscopic sample volume, and the measured diffraction pattern is the sum of the responses from the microscopic coherently diffracting domains. These experiments have utilized a Marx-generated, cable-coupled, needle-and-washer diode that emits a 40 ns pulse of line-and-bremsstahlung x-rays. The x-rays are collimated by a circular pinhole, and detected by an image plate or CCD camera coupled to a phosphor. The line emission is selectable to either 0.71 A or 0.56 A, and the hard bremsstahlung direct beam provides a zero-order reference mark in the image. Results from studies of shock-loaded materials including aluminum, tin, and zirconium are shown. Planned experiments and future diagnostic development are discussed. [Preview Abstract] |
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F1.00046: New developments in multiple simultaneous diagnostics at HPCAT Guoyin Shen The HPCAT facility, located at Sector 16 of the Advanced Photon Source (APS) which is currently under a major upgrade, has been established for high-pressure research in multidisciplinary scientific areas by integrating multiple x-ray diffraction, x-ray spectroscopy, and x-ray tomography probes. Current state-of-the-art high-pressure synchrotron facilities including HPCAT are limited to spatial resolution of 3-10 $\mu $m. Since pressure is force per unit area and ultrahigh pressures are reached at diminishingly minute samples, high spatial resolution would be the key for the next-generation advancement to TPa pressures beyond the current maximum at $\sim $400 GPa, and will impact an exceedingly broad scientific frontier. These include the long-standing quest of low-temperature metallic hydrogen, and the newly recognized complexities of the apparently ``simple'' alkali metals. The order-of-magnitude higher resolutions will enable quantifications of grain-to-grain interactions under pressure, precise determinations of equations of state and pressure calibration, combinatorial studies of a large array of samples, and isolation of a $\mu $m-size single crystal from a polycrystalline aggregate. The potential impacts on high pressure research in several scientific areas will be discussed. [Preview Abstract] |
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F1.00047: EXPERIMENTAL DEVELOPMENTS: DIAGNOSTICS - PDV |
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F1.00048: Gel versus aerogel to collect high velocity ejecta from laser shock-loaded metallic targets for post-recovery analyses Emilien Lescoute, Thibaut De Ress\'eguier, Jean-Marc Chevalier Soft recovery of fast objects is an issue of considerable interest for many applications involving shock wave loading, such as ballistics, armor design, or more recently laser-driven inertial confinement fusion, where the characterization of the debris ejected from metallic shells subjected to intense laser irradiation conditions the design of the experiments. In this paper, we compare the recovery efficiency of two materials : aerogel (density 0.03 g/cm3), which has been used as fragment collector for many years, and `varagel' (density 0.9 g/cm3), which we have tested recently (E. Lescoute et al., Shock Compression of Condensed Matter 2009). Experiments have been performed on the Alis\'{e} laser facility in the Centre d'Etudes Scientifiques et Techniques d'Aquitaine (CESTA, CEA) on 20 $\mu $m-thick aluminium targets. Transverse shadowgraphy provides quasi-instantaneous, successive pictures of the debris clouds and mean ejection velocities. Ejected fragments have been recovered in both types of collectors, then, samples have been analysed by x-ray tomography at the European Synchrotron Radiation Faciliy (ESRF). Three-dimensional reconstructions of the fragment populations have been achieved, and quantitative comparisons between both collecting materials, used in the same conditions, could be performed. [Preview Abstract] |
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F1.00049: Dynamics of the detonation products of a TATB based high explosive: Photon Doppler Velocimetry and high-speed digital shadowgraphy of expanding species Arnaud Sollier, Viviane Bouyer, Louis-Pierre Terzulli, Michel Doucet, Philippe Hebert, Lionel Decaris The present investigation attempts to further improve our experimental characterization of the reaction zone in plastic bonded high explosives, by focusing on the dynamic of expansion of the detonation products during its initial stage. To this purpose, we performed measurements of the free surface velocity history of the detonating explosive using a PDV velocimeter system developped at CEA. We also used digital high-speed shadowgraphy to characterize the shape and speed of the products as they release from the bare charge free surface. In our experiments, we used cylindrical samples of an insensitive triaminotrinitrobenzene (TATB) composition having a density about 1.86 g/cc. Most of the experiments were performed in a cylindrical chamber under vacuum, but some shots were also performed with air at atmospheric conditions. The results of these experiments are compared with those of thin push-plate and explosive-window interface velocity measurements performed in the same conditions, which allow to give new insight into the reactions zone. Numerical simulations with different reactive flow models are also presented and found to be in good agreement with experiments. [Preview Abstract] |
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F1.00050: A multi-phase Equation of State diagnostic applied to the study of shock loaded tin Caroline Shenton-Taylor, Antony Glauser, Thomas Ota, Ed Price The accurate detection of shock driven material phase transitions demands a multiple diagnostic capable of simultaneously measuring temperature, emissivity, pressure and velocity. By combining optical pyrometry with reflectivity based emissivity diagnostics we report shock loaded tin temperatures from 820 K to 1780 K with associated probable errors down to +/- 12.8 K. In addition simultaneous Class 4 laser heterodyne velocimetry recorded the tin surface velocity as viewed through a LiF anvil. Constraining the tin pressure with lithium fluoride generated microsecond experiment time durations; thermal diffusion models identified the tin/glue/LiF layer as advantageous for temperature measurement. Across a range of pressures, the emissivity corrected temperature data were found to be well aligned with a single tin Equation of State model. AWE {\copyright} Crown Owned Copyright (2011) [Preview Abstract] |
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F1.00051: ABSTRACT WITHDRAWN |
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F1.00052: Study of dynamic compression properties of H-K9L glass with prefabricated internal defects Changming Hu, Xiang Wang, Lingcang Cai, Cangli Liu The shock compressed behavior of H-K9L glass with initial inner prefabricated defects was experimentally studied in this paper. All impact tests are conducted on powder gun and the measurement system is high time-spatial resolution DPS array, which time and spatial resolution was 50 ps and 127 $\mu $m respectively. The results show the subtle difference in the velocity reached its maximum, together with the saltation velocity of 1m/s caused by the defects, which were preliminarily considered to be resulted from the spread of defect shock compression wave. In the meantime, based on the experimental results, it was deduced that there was a compression breaking stress threshold value in the prefabricated damage region under the shock compression. According to these experimental investigations, the limitation and immaturity of high time-spatial resolution DPS array measurement system were mentioned respectively, especially, the effective recording time was sacrificed on account of considering high time-spatial resolution. [Preview Abstract] |
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F1.00053: The Miniaturization and Reproducibility of the Cylinder Expansion Test Chad Rumchik, Rachel Nep, George Butler, C. Michael Lindsay The cylinder expansion test (aka Cylex) is a standard way to measure the Gurney energy and determine the JWL coefficients of an explosive and has been utilized by the explosives community for many years. More recently, early time shock information has been found to be useful in examining the early pressure time history during the expansion of the cylinder. Work in the area of nanoenergetics has prompted Air Force researchers to develop a miniaturized version of the Cylex test, for materials with a sufficiently small critical diameter, to reduce the cost and quantity of material required for the test. This paper will cover the development of the half inch diameter miniaturized Cylex test as well as the results of a measurement systems analysis performed on the miniaturized test and the one inch diameter standard Cylex test using nitromethane sensitized with EDA as the explosive. Both tests yielded the same Gurney values with similar levels of variability - approximately 2{\%}. [Preview Abstract] |
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F1.00054: EXPERIMENTAL DEVELOPMENTS: LOADING TECHNIQUES - E.G. ICE |
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F1.00055: Isentropic Compression Experiments at Imperial College Simon Bland, G. Burdiak, J. Skidmore, G. Swadling, J.P. Chittenden, M. Weinwurm, S.V. Lebedev, G.N. Hall, F. Suzuki-Vidal, L. Pickworth, P. Cong We report on initial isentropic compression experiments carried out in the Institute of Shock Physics at Imperial College London. The 1.5MA MAGPIE generator and newly commissioned 2MA MACH generator were both used to drive strip lines of various materials and thicknesses and the motion of the electrodes monitored with Het-V and laser probing. Plans for future experiments are presented including heated and cryogenic targets for studying phase changes under pressure; and the addition of external magnetic fields for shear strength measurements. New methods to drive targets to higher pressures are also discussed; along with the use of diagnostics including X-ray diffraction and scattering. [Preview Abstract] |
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F1.00056: Direct Observation of Laser-driven Plasma Loader for Shockless Compression Mu Li, Guanghua Chen, Xiuguang Huang, Jintao Cai, Zhuowei Gu, Shouxian Liu, Hongping Zhang, Jianheng Zhao, Chengwei Sun, Sizu Fu The objective of the current study tried to map out a whole procedure of laser-driven plasma jet and shockless compression of solid materials. The experiment was performed using the Shenguang-II Nd: glass laser. Transmitting and dumping of ablation shock wave in reservoir was recorded by a 2-channel line VISAR. Streaked and separated shade graph of plasma jet from rear surface of reservoir gave the plasma configuration and front speed (from 20km/s to 60km/s). A coaxial M-Z interferometer system measured density distribution at the front of plasma loader. It can be seen that the density distribution bulges downward near the front of the plasma jet, which is an important characteristic that determines shockless compression. And 10/20$\mu $m Al foil backed by 1mm LiF were compressed to 40GPa. [Preview Abstract] |
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F1.00057: EXPERIMENTAL DEVELOPMENTS: LATERAL GAUGE MEASUREMENTS |
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F1.00058: On the importance of encapsulation environment for lateral gauges in Tantalum Jonathan Painter, Gareth Appleby-Thomas, Paul Hazell, Ronald Winter, Ernst Harris, Gareth Owen, David Wood In principle, embedded wire-element lateral manganin pressure gauges allow the lateral component of stress during shock loading to be directly monitored. However, such gauges require target materials to be sectioned before gauge insertion into an encapsulating Mylar/epoxy layer, leading to debate over their interpretation. In particular, recent computational modelling has suggested, amongst other factors, gauge response may be linked to the nature of material flow within the gauge encapsulation under shock loading. Here, this phenomenon was experimentally investigated by variation of the geometric environment of embedded lateral T-gauges (Vishay Micro-Measurements{\textregistered} type J2M-SS-580SF-025) in Tantalum (Ta) targets. In particular, inclusion of cover and backing plates allowed restriction of encapsulation material flow under shock. Subsequent comparison to the response of ``classically-encapsulated'' lateral gauges facilitated additional insights into lateral gauge interpretation. [Preview Abstract] |
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F1.00059: Experimental and computational investigation of lateral gauge response in polycarbonate Jim Eliot, Ernst Harris, Paul Hazell, Gareth Appleby-Thomas, Ronald Winter, David Wood, Gareth Owen Polycarbonate's use in personal armour systems means its high strain-rate response has been extensively studied. Interestingly, embedded lateral manganin stress gauges in polycarbonate have shown gradients behind incident shocks, suggestive of increasing shear strength. However, such gauges need to be embedded in a central (typically) epoxy interlayer -- an inherently invasive approach. Recently, research has suggested that in such metal systems interlayer/target impedance may contribute to observed gradients in lateral stress. Here, experimental T-gauge (Vishay Micro-Measurements{\textregistered} type J2M-SS-580SF-025) traces from polycarbonate targets are compared to computational simulations. This work extends previous efforts such that similar impedance exists between the interlayer and matrix (target) interface. Further, experiments and simulations are presented investigating the effects of a ``dry joint'' in polycarbonate, in which no encapsulating medium is employed. [Preview Abstract] |
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F1.00060: Lateral stress measurements in dense suspensions Oren Petel, David Frost, Andrew Higgins, Simon Ouellet Piezoresistive stress gauges are often used as a means of experimentally measuring the dynamic strength of materials. This procedure involves measuring the principal stresses in a material resulting from the uniaxial strain loading of a planar impact. The present study investigates the deviatoric response of dense particle suspensions consisting of silicon carbide suspended in ethylene glycol. The validity of the method is first shown in a pure liquid environment, recovering the hydrodynamic behaviour of the liquid experimentally, before it was applied to measure the response of the suspension. The deviatoric response of the dense suspension indicates that there is a shock-induced stiffening within the mixture. A meshless numerical approach (SPH) is used to investigate the shock-induced mesostructural deformation of the suspension. The measured deviatoric response of the suspensions is discussed in terms of the formation of inter-particle contact networks, which results from the shock-induced mesostructural changes in the suspensions. [Preview Abstract] |
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F1.00061: The effect of gauge misalignment on the measurement of lateral stress Gareth Appleby-Thomas, Paul Hazell, Andrew Roberts The evolution of the lateral component of stress during shock loading may be directly interrogated via embedded wire-element lateral manganin pressure gauges. However, these gauges are an inherently invasive diagnostic, requiring target materials to be sectioned before insertion. Further, they inevitably possess a significant finite size; with typical active element widths of c.15 mm. Consequently, gauge insertion, typically within an encapsulating epoxy interlayer, can lead to some degree of misalignment. In order to quantify any effects of such experimental errors, the response of Vishay Micro-Measurements T-gauges of type J2M-SS-580SF-025 was monitored in PMMA targets machined such that embedded gauges were deliberately misaligned to a known extent. Attempts were made to link the extent of misalignment to gauge response for misalignments introduced both in the plane of, and orthogonally to, the impact axis. [Preview Abstract] |
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F1.00062: ENERGETIC MATERIALS |
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F1.00063: Size Effect and Cylinder test on Several Commercial Explosives Lisa Lauderbach, Kou Moua, Raul Garza, Clark Souers The size (diameter) effect and the Cylinder test results for ammonium nitrate/nitromethane, some ammonium nitrate/fuel oil mixes, Red Dot shotgun powder, Semtex 1A and Semtex H will be presented. A generalized detonation velocity format , valid for all detonation rates, will be discussed. A shot in cylindrical symmetry will be compared with the 1-D cylindrical size effect data. [Preview Abstract] |
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F1.00064: New Mix Explosives for Explosive Welding Leonid Andreevskikh Suggested and tested were some mix explosives---powder mixtures of a brisant high explosive (HE = RDX, PETN) and an inert diluent (baking soda)---for use in explosive welding. RDX and PETN were selected in view of their high throwing ability and low critical diameter. Since the decomposition of baking soda yields a huge amount of gaseous products, its presence ensures (even at a low HE percentage) a throwing speed that is sufficient for realization of explosive welding, at a reduced brisant action of charge. Mix chargers containing 30--70 wt {\%} HE (the rest baking soda) have been tested experimentally and optimized. For study of possibility to reduce critical diameter of HE mixture, the mixture was prepared where HE crystal sizes did not exceed 10 $\mu $m. The tests, which were performed with this HE, revealed that the mixture detonated stably with the velocity D $\approx $2 km/s, if the layer thickness was d = 2mm. The above explosives afford to markedly diminish deformations within the oblique impact zone and thus to carry out explosive welding of hollow items and thin metallic foils. [Preview Abstract] |
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F1.00065: Development of the Floret Test for Screening the Initiability of Explosive Materials Mark Wright The Floret test was developed as a small scale screening experiment to characterise the initiability and divergence of novel explosive train materials; providing a route to undertake initial optimisation of explosive formulations. The test utilises an explosively driven, aluminium flyer plate to impact a 12.6 mm diameter, by 4 mm long explosive sample; the output from which is characterised by profiling the dent imparted into an adjacent copper witness block. The aluminium flyer plate characteristics are varied in order to assess the initiability of the samples, yielding an estimate of the initiation spot size for the explosive. Additionally, the effect of density on initiability can be characterised to optimise the sample properties to those that best fit the programme requirements. A summary of the results on the use of the Floret test to optimise the formulation and density of booster materials will be reported. Furthermore, work undertaken to characterise and tune the aluminium flyer plate will be presented, including velocimetry measurements and studies to widen the initiation parameters of the test. These results have improved understanding of the initiation characteristics of the Floret test and, using a case study of optimising the test to study HMX based materials, provided insight into the initiation behaviour of explosive materials to flyer plate impacts. [Preview Abstract] |
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F1.00066: Confiner-Wall Motion as a Diagnostic in Cookoff Experiments Larry Hill, Daniel Hooks, Timothy Pierce The use of wall motion as a diagnostic in detonation experiments dates to G.I. Taylor's famous 1941 wartime analysis. A handful of authors (including us) have since used it to analyze the detonation copper cylinder test for equation-of-state information. In addition, we have successfully applied Taylor's analysis to specialized deflagration waves, the behavior of which reasonably mimics that of the detonation copper cylinder test at a greatly reduced rate. Here we present a similar analysis of a miniature deflagration cylinder test, in which the copper tubes simply bulged to a pressure burst. The tube motion was diagnosed with a series of pdv probes, which gave continuous time records at discrete axial locations. We begin by spatially interpolating to obtain continuous records in the axial direction. This allows us to calculate the interior product gas volume at any time, and to generate movies of the tube swelling to rupture. Finally, combining Newton's law with membrane theory, we estimate the gas pressure driving the burst. [Preview Abstract] |
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F1.00067: Violent cookoff reactions in HMX-based explosives in DDT tubes: tracking luminous waves with streak imaging Gary Parker, Peter Dickson, Blaine Asay, Laura Smilowitz, Bryan Henson, John McAfee The authors present data from a series of high-temperature deflagration-to-detonation (DDT) tube experiments where the HMX-based high explosives PBX 9501 and LX-07 were heated above 180$^{\circ}$C for various durations to impose damage (i.e. phase transitions and void generation) before being driven to cook off. These explosives have different polymeric binders, HMX mass fractions and cookoff responses and a comparison between the two offers revealing mechanistic insights on how thermal explosions evolve. From this series, results will be displayed indicating a wide range of violence from somewhat mild pressure bursts, to intermediate-power compressive burns, to high-violence DDT. Image data from high temperature DDT tube experiments, where the explosive was ignited on one end, were also collected and will be included for comparison. Analysis of the end-ignited streak images reveals characteristics that support established theories invoking a variety of burn modes in porous beds. Interestingly, from the cookoff experiments, the mechanism for build-up to DDT appears truncated. This analysis and its potential implications for modeling cookoff will be presented. [Preview Abstract] |
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F1.00068: ABSTRACT WITHDRAWN |
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F1.00069: Mesoscale Modeling of Deflagration-Induced Deconsolidation in Polymer-Bonded Explosives H. Keo Springer, J.E. Reaugh, E.A. Glascoe, J.R. Kercher, G. Friedman Initially intact polymer-bonded explosives can transition from conductive burning to more violent convective burning via rapid deconsolidation at higher pressures. The pressure-dependent infiltration of cracks and pores, i.e., damage, by product gases at the burn-front is a key step in the transition to convective burning. However, the relative influence of pre-existing damage and deflagration-induced damage on the transition to convective burning is not well understood. The objective of this study is to investigate the role of explosive constituent properties, microstructure, and deflagration velocity on deconsolidation. We performed simulations using the multi-physics hydrocode, ALE3D. HMX was used as the model energetic grain. We used a JWL form for the unreacted and reacted equation-of-state of the HMX. Simplified strength and failure models were used for the HMX and the binder. The propensity for deconsolidation increased with increasing grain volume fraction, increasing porosity, decreasing binder strength, and increasing deflagration velocity. These studies are important because they enable the development of deflagration-induced damage models, as well as the design of inherently safer explosives. This work performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344. This work was funded by the Joint DoD/DOE Munitions Technology Development Program. [Preview Abstract] |
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F1.00070: Determination of the Velocity-Curvature Relationship for Unknown Detonation Front Shapes Scott Jackson, Mark Short Detonation Shock Dynamics (DSD) is a surface propagation concept that replaces the detonation shock and reaction zone with a surface that evolves according to a specified normal-velocity evolution law. DSD is able to model detonation propagation when supplied with two components: the normal-detonation-velocity variation versus detonation surface curvature and the surface edge angle at the explosive-confiner interface. The velocity-curvature relationship is derived from experimental rate-stick data. Experimental front shapes can be fitted to an analytic equation with a similar characteristic shape and the detonation velocity-curvature relationship computed from that analytic expression. In some complex explosive-confiner configurations, an appropriate functional form for the detonation front shape may be difficult to construct. To address such situations, we numerically compute the velocity-curvature relationship directly from discrete experimental front-shape data with no assumptions of wave shape. The results are then compared to the analytic method for determining the velocity-curvature relationship. The possibilities and limitations of such an approach are discussed. [Preview Abstract] |
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F1.00071: Cookoff of Non-Traditional Detonators Jonathan Zucker, Bryce Tappan, Virginia Manner, Alan Novak Significant work has gone into understanding the cookoff behavior of a variety of explosives, primarily for safety and surety reasons. However, current times require similar knowledge on a new suite of explosives that are readily attainable or made, and are easily initiated without expensive firesets or controlled materials. Homemade explosives (HMEs) are simple to synthesize from readily available precursor materials. Two of these HMEs, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) are not only simple to prepare, but have sufficient output and sensitivity to act as primary explosives in an initiation train. Previous work has shown that detonators may be an integral vulnerability in a cookoff scenario. This poster contains the results of cookoff experiments performed on detonators made with TATP and HMTD. We found that the less chemically stable TATP decomposed during heating, while the more chemically stable HMTD acted like a traditional primary explosive, namely reaction violence and time-to-ignition were independent of confinement. [Preview Abstract] |
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F1.00072: The Behavior of Plasma Gases in Explosively-Driven Plasma Generator Minsu Seo, Jin Soo Choi, Inho Kim The plasma-hydrodynamic computer simulation has been performed in order to investigate the thermodynamic and electrical properties of plasma generated in an explosively-driven cylindrical plasma generator. An one-dimensional hydrodynamic code, One-D, was written for this study and a realistic plasma equation of state model was applied to the code. A couple of plasma generators were manufactured and filled by dry air or pressurized argon gas for plasma medium. The plasma thickness and flow velocity were measured by utilizing the optical and electrical pins. The simulation results of the plasma characteristics were in good agreement with the measured values. [Preview Abstract] |
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F1.00073: Coupled Eulerian/Lagrangian Simulation for Overpressure Structural Response Andrew Lloyd, Hua Pan, David Miller, John Cogar Accurately modeling blast dynamics is critical in the assessment of structures subjected to blast loading. The current industry standard for modeling blast effects in Lagrangian based Finite Element simulations is CONWEP; tabulated pressure data taken directly from blast events. CONWEP is limited, however, and may not always be physically representative of the blast/structural interaction that occurs in the field. Eulerian hydrocodes provide advantages over CONWEP in that they can capture shock front interaction and model blast surface interfaces with fidelity due to the presence of the working fluid. Eulerian codes, however, break down over larger time scales; whereas, Lagrangian modeling allows for discrete finite elements with definable boundary interfaces that can be tracked out to longer time scales. Hence, a hybrid approach that couples the Eulerian blast modeling with Lagrangian system dynamics is necessary. The objective of this paper is to demonstrate improvements in overpressure structural response modeling using a Coupled Eulerian/Lagrangian algorithm implemented in VelodyneTM. Velodyne results using the Coupled Eulerian/Lagrangian algorithm are compared to results from Eulerian hydrocode simulations and Velodyne simulations using the CONWEP algorithm. [Preview Abstract] |
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F1.00074: Small-scale Explosives Sensitivity Safety testing-A Departure from Bruceton Daniel Preston, Geoffrey Brown, Cary Skidmore, Bettina Reardon, David Parkinson In order to safely work with explosives, their sensitivity to external stimuli needs to be characterized. The Bruceton method for evaluating sensitivity results has been used for over six decades. This has included the skid test on the large scale, and the friction and drop weight impact tests on the small scale. The result was a 50 percent probability of reaction, useful for ranking the comparative responses of explosives in order to make a practical assessment of handling safety. This paper summarizes the limitations of the Bruceton method and introduces the efficacies of the D-optimal test method. A comparison of the two approaches is provided using results for PETN, HMX, and other explosives. Los Alamos Type 12 Drop Weight Impact apparatus is used to generate and compare 50 percent drop heights using the Bruceton and D-optimal methods. The results show that the means obtained by the Bruceton or D-optimal methods are not statistically different, alleviating concerns about departing from a historical database. The D-optimal method uses a larger step size between consecutive tests to converge on the 17 percent and 83 percent probability points. In the presentation we will also discuss details of our historical Bruceton testing for impact and friction sensitivity and how these tests are currently evolving in our facilities. [Preview Abstract] |
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F1.00075: A Study of Fragmentation in a Ni-Al Structural Energetic Material B. Aydelotte, C.H. Braithwaite, N.N. Thadhani, M. Trexler, D.M. Williamson A study of fragmentation behavior of a Ni-Al structural energetic material was undertaken to determine fragment size and distribution as well as study the impact of material microstructure on the fragmentation process. Rings were fabricated from a nearly 100{\%} TMD Ni-Al structural energetic material and subjected to explosive fragmentation experiments. Fragments were recovered for subsequent analysis; PDV velocity data was concurrently collected. Recovered fragments show negligible ductility suggesting that brittle fracture behavior dominates the fragmentation process. Quantitative microscopy and comparisons with existing fragmentation models are presented. [Preview Abstract] |
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F1.00076: The Effect of Localised Short Duration Thermal Insults on HMX based Explosives Steve Wortley This paper describes some experiments undertaken to address a specific concern regarding the susceptibility of a bare HMX based explosive charge to an extremely hot source but with a short duration of application such as a metal spark arising from a cutting operation or a single drop of hot material. In a short series of experiments small pressed charges of HMX formulated with Viton where heated by the application of a pre-heated thermocouple. The temperature of the thermocouple and the duration of the contact were varied and the response of the explosive was observed. In general the explosive was remarkably tolerant of the thermal insult. However, at the highest test temperatures and at the longest durations ignitions leading to prolonged burning were observed. Although materials in these experiments were undamaged prior to application of the thermal insult this data may help to understand the likely response of explosives to bullets or fragments preheated by penetration of protective layers. [Preview Abstract] |
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F1.00077: Computed Ranking-Hugoniot relations for hexanitrostilbene and hexanitrohexaazaisowurtzitane via density functional theory based molecular dynamics Ryan Wixom, Ann Mattsson, Thomas Mattsson Density Functional Theory (DFT) has become an in-dispensable tool for understanding the behavior of matter under extreme conditions, for example confirming experimental findings into the TPa regime and amending experimental data for constructing wide-range equations of state (EOS). The ability to perform high-fidelity calculations is even more important for cases where experiments are impossible to perform, dangerous, and/or prohibitively expensive. We will present computed shock properties for hexanitrostilbene and hexanitrohexaazaisowurtzitane, making comparisons with experimental shock data or diamond anvil cell data, where available. Credibility of the results and proposed methods for validation will be discussed. [Preview Abstract] |
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F1.00078: ABSTRACT HAS BEEN MOVED TO T1.00002 |
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F1.00079: Modeling of a random network of extended CO solids I.G. Batyrev, William D. Mattson, Betsy M. Rice This presentation will describe first principles explorations of a random network of polymeric carbon monoxide (poly-CO), a high energy density material. Starting with 128 and 432-atom unit cells of a CO molecular solid in the disordered delta phase we performed atom relaxation and conjugate gradient cell optimization at different pressures. We found that during the compression of the delta phase in the range of 10-15 GPa, random networks consisting mainly of 4 and 5 member rings with O atoms in the cage of the rings, carbonyl units and few CO molecules form. The optimized structure has triclinic and orthorhombic distortions of the initial cubic structure of less than 3{\%}. Vibrational frequencies of the random structures were calculated for comparison with FTIR and Raman spectroscopy experimental data. Additionally, the electron localization function and Bader analysis are used for understanding of stability and sensitivity of the extended CO structures. [Preview Abstract] |
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F1.00080: A Mitigation Scheme for Underwater Blast: Experiments and Modeling Lee Glascoe, Larry McMichael, Kevin Vandersall, Jon Margraf A novel but relatively easy-to-implement mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated experimentally using scaled aquarium experiments and numerically using a high-fidelity finite element code. Scaled, water-tamped explosive experiments were performed using aquariums of two different sizes. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an air-filled media mitigation concept were found to effectively dampen the explosive response of an aluminum plate and reduce the final displacement at plate center by approximately half; an experiment using an air-gap alone resulted in a focused water jet. The finite element model used for the initial experimental design compares very well to the experimental DIC results both spatially and temporally. Details of the experiment and the finite element models of the aquarium, as well as a larger hypothetical structure, are described including the boundary conditions, numerical techniques, detonation models, experimental design and test diagnostics. This work was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344. We would like to thank DHS S{\&}T Directorate for support and assistance. [Preview Abstract] |
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F1.00081: On the thermal expansion hysteresis of a UK PBX David Williamson, Stewart Palmer, Rebecca Govier The thermal expansion coefficient of a UK PBX has been measured over the temperature range -40 to +80 \r{ }C. A subtle but measurable hysteresis in length as a function of temperature was observed. This is attributed to a miss-match between the thermal expansion coefficients of its solid-fill and binder constituents. On heating or cooling this induces mechanical stresses within the binder system, which being viscous it can flow to relieve. A change in sample temperature results in an asymptotic relaxation to a mechanical equilibrium length, which is described by an exponential dependence on time. This is analogous to the type of stress relaxation and creep behaviour normally associated with the bulk response of viscoelastic materials when more conventional stresses are applied. [Preview Abstract] |
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F1.00082: Modeling shear instability and fracture in dynamically deformed Al/W granular composites Karl Olney, David Benson, Vitali Nesterenko Aluminum/Tungsten granular composites are materials which combine high density and strength with bulk distributed fracture of Al matrix into small particles under impact or shock loading. They are processed using cold and hot isostatic pressing of W particles/rods in the matrix of Al powder. The presentation will describe modeling of these materials under dynamic conditions simulating low velocity high energy impact in drop weight test (10 m/s) and also behavior following impact with velocities up to 1200 m/s. It will be demonstrated that morphology of W component and bonding between Al particles dramatically affects their strength, shear localization and mode of fracture of Al matrix. The support for this project provided by the Office of Naval Research Multidisciplinary University Research Initiative Award N00014-07-1-0740 (Program Officer Dr. Clifford Bedford). [Preview Abstract] |
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F1.00083: Kinetics Modeling and Numerical Simulation of Reactive Materials Sunhee Yoo, D. Scott Stewart, David E. Lambert, Sunjin Choi Simulations with reduced kinetic models are used to study shock ignition and detonation in reactive materials that may support non-classical detonation. Porous aluminum Teflon oxidizer mixtures that support combustion reactions in air are considered, as a member of a class of materials with intrinsic interest. We recast a phenomenological theory\footnote{Yoo, S., D.S. Stewart, and D.E. Lambert, ``Modeling a Supersonic Solid State Detonation in an Overdriven Porous Mixture of Aluminum and Teflon,'' J. Mat. Sci. Forum V. 673, Explosion, Shock Wave, and High-Energy Reaction Phenomena, Sept 2010} with realistic kinetics with end products; AlF$_3$, C and CO$_2$. Intermediate products include at least thirty elementary reactions; a sub-set can be selected to simplify, but a hard problem remains. We use the multi-scale asymptotic ``G-scheme'' proposed by M. Valorani, S. Paolucci and reduce a dynamical system consisting of the intermediate reactions and rates, conservation laws and porosity evolution. Results of the multi-species evolution and its impact on rapid self-oxidizing combustion and possible detonation conditions and the computational methods are presented. [Preview Abstract] |
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F1.00084: Mesoscale Studies of Mixing in Reactive Materials During Shock Loading Ilya Lomov, Eric Herbold One of the requisite processes for reactions between solid powder particles resulting from shock loading is that they undergo large deformations, exposing new surfaces while mixing with surrounding material. The deformability of Al particles on the scale of hundreds of nanometers to several microns with an oxide layer or Ni coating during shock loading is investigated. Mesoscale simulations with an Eulerian hydrocode GEODYN show enhanced fracture of the outside layer of the Al particles when even small volume fractions of a larger or dense material is added to the mixture. Rate of reactions in solid- solid mixtures is not a unique function of pressure, temperature and the plastic strain. Reactions under shock loading happen in reaction zone, which extent is defined by the surface of interfacial area and the depth of the diffusion layer. The former depends on the level of hydrodynamic mixing of heterogeneous material under shock, while the latter depends on the temperature-dependent species diffusion. These processes introduce time and length scales onto the problem. To study diffusion-limited reactions on the grain scale level, material diffusion and a simple reaction kinetic which depends on the interfacial surface area is implemented in GEODYN. Several scenarios of diffusion-reaction processes initiated by shock loading in loose or consolidated powders with initially well- defined material interfaces are considered. [Preview Abstract] |
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F1.00085: Roles of processing and mesostructure on dynamic properties of Al/W granular composites Po-Hsun Chiu, Chien-Wei Lee, Vitali Nesterenko High density Al-W granular/porous composites were fabricated using (a) Cold Isostatic Pressing (CIPing) with subsequent Hot Isostatic Pressing (HIPing) with vacuum encapsulation or (b) CIPing followed by vacuum sintering plus HIPing without vacuum encapsulation. All samples had an identical weight ratio between Al and W with different porosities, size, shape and orientation of W component and also different size of Al particles. Their dynamic strength and fracture were investigated at strain rate 1000 1/s. Size of W and Al particles, bonding between Al particles and morphology of W inclusions had a strong effect on dynamic strength and shear instability of the materials. [Preview Abstract] |
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F1.00086: Fluoropolymer and Aluminum Piezoelectric Reactives Robert Janesheski, Steven Son, Lori Groven The ability to sensitize a nanoaluminum/piezoelectric polymer composite has been studied using two fluoropolymer systems (THV220A and FC-2175). Fluoropolymers were chosen based on the presence of vinylidene fluoride (VDF) that is known to exhibit piezoelectric properties in certain phases. Reactive composite samples of the nanoaluminum/polymer were made into thin sheets and their ability to store energy and exhibit piezoelectric properties was measured. Also, initial drop weight impact tests were performed on the samples and results showed the piezoelectric energetic composites failed to ignite at a given impact energy. However, when a DC voltage was applied to the sample, the materials ignited at the previous impact energy indicating that the reactive composites may have been sensitized by the stored charge. The application of a DC voltage may also have an effect on the piezoelectric properties of the inorganic energetic composites. Further work is planned to investigate what parameters are inducing the sensitization of the material. A better understanding could lead to applications where switching or changing the sensitization of an energetic material is beneficial. [Preview Abstract] |
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F1.00087: EQUATION OF STATE |
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F1.00088: Experimental determination of Grunieisen gamma for two dissimilar materials (PEEK and Al 5083) via the shock-reverberation technique Andrew Roberts, Gareth Appleby-Thomas, Paul Hazell Following multiple loading events the resultant shock state of a material will lie away from the principle Hugoniot. Prediction of such states requires knowledge of a materials equation-of-state. The material-specific variable Grunieisen gamma ($\Gamma )$ defines the shape of ``off-Hugoniot'' points in energy-volume-pressure space. Experimentally the shock-reverberation technique (based on the principle of impedance-matching) has previously allowed estimation of the first-order Grunieisen gamma term ($\Gamma _{1})$ for a silicone elastomer. Here, this approach was employed to calculate $\Gamma _{1}$ for two dissimilar materials, Polyether ether ketone (PEEK) and the armour-grade aluminium alloy 5083 (H32); thereby allowing discussion of limitations of this technique in the context of plate-impact experiments employing Manganin stress gauges. Finally, the experimentally determined values for $\Gamma _{1}$ were further refined by comparison between experimental records and numerical simulations carried out using the commercial code ANYSYS Autodyn{\textregistered}. [Preview Abstract] |
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F1.00089: Improvements of the CARTE thermochemical code dedicated to the computation of properties of explosives Nicolas Desbiens, Vincent Dubois, Christophe Matignon, Remy Sorin Predicting the thermodynamic properties of detonation products and the detonation parameters of explosives with thermochemical codes requires both the use of very accurate theoretical equations of state of fluid species and a precise calibration of the parameters of the species potentials. In this work, we present the methods used in the CARTE$^{(1)}$ thermochemical code. The detonation product mixture is split in two phases (fluid phase plus condensed phase for the carbon). The improved KLRR$^{(2)}$ method and a modified Van der Waals -- one fluid model$^{(3)}$ are used to compute the properties of the mixture. The usual Ree -- Van Thiel equation of state for carbon is used. Ionic/polar species are taken into account by the use of methods already published in the literature$^{(4)}$. We also consider a multiphase EOS model of carbon which evolves with the chemical composition of the explosives. The calibration of the parameters is then performed with a Monte Carlo minimisation method against a wide range of both theoretical and experimental data. This reference data base is mainly composed of shock or static compression data. Finally, we present some results obtained on a wide range of explosives. (1) Dubois et al., Chem. Phys. Lett., 494, 2010, p 306 (2) Victorov et al., Proc. of the 13$^{th}$ Int. Deto. Symp., 2006 (3) Desbiens et al., Proc. of 8$^{th}$ New Models and Hydrocodes, 2010 (4) Bastea et al., Proc. of the 13$^{th}$ Int. Deto. Symp., 2006 [Preview Abstract] |
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F1.00090: Dynamic behaviour of KDP for laser-induced damage applications David Hebert, Ludovic Hallo, Luc Voisin, Thierry Desanlis, Alain Galtie, Beatrice Bicrel, Cedric Maunier, Patrick Mercier, Guillaume Duchateau High power lasers as NIF in the USA or LMJ in France are being developed in order to produce inertial fusion confinement. However, the efficiency of these apertures is limited by laser-induced damage which occurs in the potassium dihydrogen phosphate (KDP) crystals allowing the frequency conversion. We present here hydrodynamic simulations that investigate the major processes following absorption of the laser energy on precursor defects, leading to the creation of a shock wave whose pressure lies in the GPa range. An associated rarefaction wave forms a cavity at the place of the precursor defect. In order to perform quantitative predictions, a reliable equation of state is required, along with strength properties. A review of available experimental data is presented and used to discuss the validity of different models for KDP. [Preview Abstract] |
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F1.00091: Anomalous Wave Structure in Diverging Geometry by Non-convexity of the Equation of States Kyuwan Hwang It is well known that a non-convex equation of states(EOS), which is defined by Thompson's ``fundamental derivative'' $\cal G$ being negative, can be developed for materials near phase transition, or plasma under specific conditions. Non-convexity of EOS leads to anomalous wave structure including rarefaction shock and composite waves as solution of the scale-invariant Riemann problem in flat geometry. This phenomenon is well understood and compiled into excellent review papers, for example Menikoff and Plohr. Recently, a numerical study is performed using a model EOS by Heuze, at. al. In this presentation, we studied numerically the anomalous wave structure developed by non-convex EOS in the system with geometric divergence, which breaks the scale invariance assumption. [Preview Abstract] |
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F1.00092: Hugoniot and Properties of Diesel Fuel Used in ANFO David L. Robbins, Stephen A. Sheffield, Dana M. Dattelbaum, David B. Stahl One of the more common ammonium nitrate (AN) based explosive is called ANFO, which is a mixture of AN prills and diesel fuel oil (FO) in a 94:6 ratio by weight. Since there is no available shock data on FO, a series of shock compression experiments have been completed on a two-stage light gas gun with a sealed liquid target cell. We have chosen a representative grade of fuel oil (diesel) for our experiments. Knowing that all FO is not the same, we decided to study this material, assuming it is representative. Density and sound speed data were measured, and used to predict the unreacted Hugoniot. The data were found to compare well with a universal liquid Hugoniot. In-situ magnetic gauges in the target cell were used to measure the particle velocity, shock velocity, and shock wave profiles. Impact velocities ranged from 1.5 to 3.2 km/s generating shocked pressures between 3 and 17 GPa, depending on the impactor material being used. The FO Hugoniot is being used in conjunction with ongoing ammonium nitrate (AN) shock compression measurements to further understand the unreacted Hugoniot of the ANFO mixture. Additionally, wave profiles and the Hugoniot are analyzed to determine if shock-induced reaction occurs, within the pressure range studied. [Preview Abstract] |
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F1.00093: The Effects of Relativity on First-Principles Calculations T. Semi, A.E. Mattsson, J.M. Wills The construction of the equation of state for a given material is of central importance to its characterization. Hugoniots can be calculated using Density Functional Theory (DFT), and DFT points compared to available experimental results. By evaluating the accuracy in a relevant phase space, confidence is gained in the DFT method. This bolsters the dependability of DFT data in phase spaces in which experiment may be difficult or impossible to perform, and verifies its usefulness. The equation of state is comprised of the cold curve and thermal electronic and ionic terms. We discuss differences in the cold curve of Ce produced by first principles calculations using the Scalar Dirac equation with variational spin-orbit coupling treatment and that generated by the full relativistic formulation, both with the same DFT functionals. The relativistic effects of f-electrons in systems like Ce are expected to be of a magnitude substantial enough to be consequential to the description of these structures. ``Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000." [Preview Abstract] |
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F1.00094: Shock Data Base Igor Lomonosov, Konstantin Khishchenko, Pavel Levashov, Dmitry Minakov, Alexey Zakharenkov Shock-wave data provide for the reference information for testing and validating theoretical models. Measurements of principal, reflected and porous Hugoniots and determinations of release isentrope parameters cover a broad range of the phase diagram. This unique information embraces nine orders with respect to pressure and five orders with respect to density. All of the data are unique, have their own history and present a result of complicated expensive experiments. We have collected about 20000 experimental points on shock compression, adiabatic expansion, measurements of sound velocities behind the shock front and free-surface-velocity profiles for more than 650 substances. The database with graphical user interface containing experimental data and typical 1D computational experimental setups has been worked out. One can search the information in the database and obtain the experimental points in tabular or plain text formats directly via the Internet using common browsers. It is also possible to draw the experimental points on graphs in comparison with different approximations and results of equation-of-state calculations. One can present the results of calculations in text or graphical forms and compare them with any experimental data available in the database. [Preview Abstract] |
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F1.00095: The Single Phase and Two-phase Equations of State for Aluminum Liu Haifeng, Song Haifeng, Zhang Gongmu We present a single phase and a two-phase(solid-liquid) equations of state (EOS) for aluminum. The single phase EOS is based on the theory of Born. The free energy contains three terms. The 0K static energy is expressed as the Born-Mayer potential, the thermal free energy from electronic excitations is formulated as Al'tshuler's model, and the vibrational free energy of the lattice ion is expressed as the modified Debye model, which considers the high-temperature anharmonic effects by the empirical interpolation between a solid under normal conditions and an ideal gas. The two-phase EOS follows the method used by Chisolm et al to determine solid and liquid EOS for aluminum. The two equations reproduce the experimentally measured Hugoniot data and melting curve. It is shown that the difference between two equations is obvious on the boundary of solid and liquid. We also discuss the range of validity for the EOS. These results allow us to comment the effect of melting on EOS. [Preview Abstract] |
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F1.00096: Multiphase Equation of State for Iron at High Dynamic Pressures Konstantin V. Khishchenko Equations of state for materials over a wide range of densities and temperatures are needed for hydrodynamic simulations of processes in shock-compressed media. In the present work, a new multiphase equation of state for iron is proposed with taking into account the polymorphic phase transformations, melting, evaporation and ionization. Results of calculations of thermodynamic parameters of the three solid ($\alpha$, $\varepsilon$ and $\gamma$) as well as the liquid and gas phases of Fe are compared with available experimental data at high dynamic pressures. [Preview Abstract] |
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F1.00097: International Shock-Wave Database: Systematization of Experimental Data Pavel R. Levashov, Konstantin V. Khishchenko, Igor V. Lomonosov, Dmitry V. Minakov, Alexey S. Zakharenkov In this work, we announce the creation of the International Shock-Wave Database (ISWDB). Shock-wave and related dynamic material response data serve for calibrating, validating, and improving material models over very broad regions of the pressure--temperature--density phase space. Our objectives are (i) to develop a database on thermodynamic and mechanical properties of materials under conditions of shock wave and other dynamic loadings, selected related quantities of interest, and the meta-data that describes the provenance of the measurements and material models, and (ii) to make this database available internationally thru the Internet, in an interactive form. The development and operation of the ISWDB will be guided by input from a steering committee. The database will be installed on two mirrored web-servers, one in Russia and the other in USA. The database will provide access to original experimental data on shock compression, non-shock dynamic loadings, isentropic expansion, measurements of sound speed in the Hugoniot state, and time-dependent free-surface or window-interface velocity profiles. We believe that the ISWDB will be a useful tool for the shock-wave community. [Preview Abstract] |
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F1.00098: GEOPHYSICS AND PLANETARY SCIENCE |
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F1.00099: Rock-forming Minerals Transformations in Conditions of Stepwise Shock Compression of Qwartz-feldspar-biotite-garnet Schist from Southern Ural Irina Belyatinskaya, Vilen Feldman, Vladimir Milyavskiy, Tatiana Borodina Samples for experiments with use of recovery assemblies of planar geometry have been taken from Southern Ural (Russia). The maximal shock pressures in the samples were attained upon a few reverberations of the waves between the walls of the recovery ampoule (stepwise shock compression) and were equal 26, 36 and 52 GPa. Shock-metamorphic transformations of rock-forming minerals (garnet, biotite, quartz, potash feldspar and plagioclase) have been studied with the use of optical and scanning electron microscopy (SEM) methods, microprobe analysis, and X-ray phase analysis (XPA). The strongest transformations (mechanical and chemical) were observed in potash feldspar and plagioclase. These minerals undergo strong amorphization at 26 GPa already. Plagioclase chemical transformations are equal to results of earlier stepwise shock compression experiments [1]. Biotite also reveals strong mechanical (kink-bands, partial melting) and chemical (for melted biotites only) transformations. Garnet reveals mechanical transformations only. 1. Belyatinskaya and others. // Moscow University Geol. Bull., 2010, Vol. 65, No. 5, pp. 289--300 [Preview Abstract] |
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F1.00100: Observation of the mass and velocity of projectile fragments produced by hypervelocity impact with light-weight ceramic targets Fumikazu Saito, Nobuaki Kawai, Hideki Tamura In order to characterize dynamic fracture of Al projectiles caused by impact with light-weight ceramic targets, we performed hypervelocity impact experiments of light-weight ceramic targets using spherical Al projectile accelerated by mini two-stage light-gun. As ceramic targets, Mullite, Silicon nitride, and Alumina ceramics with 1 mm thick are chosen. Aluminum-alloy projectiles of 2.1 mm in diameter are accelerated up to 4.8 km/s and impacted onto the targets under normal impact condition. The dynamic fracture of targets and projectiles is observed with flash, soft x-ray radiography and high speed digital framing camera photography, and we propose a new method for calculating the mass of impact fragments by means of flash x-ray and x-ray imaging plate. A witness plate is used to evaluate a protective performance of the targets. In comparison to the results of Silicon nitride and Alumina targets, Mullite target breaks up the projectile into smaller fragments than the other targets, and the scattering angle of the debris generate from Mullite target is larger than that of the other targets. These results suggest that Mullite ceramics will be promising structural member making up debris shield. [Preview Abstract] |
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F1.00101: Laboratory impact experiments on granular materials L. Huang, W.Z. Han, X.H. Yu, H.T. Chen, S.N. Luo We perform laboratory impact experiments using a vertical gas gun on granular materials, with different impact geometry and energy, and target composition. The impactors are spheres or cylinders, and the targets include single component granular materials, and binary random or layered mixtures (one hard and one soft layer). Different impact angles are explored. For the layered mixtures, the impact direction is either normal or parallel to the layer interface. Crater morphology is characterized, and some scaling relations are presented. Our results bear implications to understanding general impact behavior of granular materials and terrestrial impact cratering. [Preview Abstract] |
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F1.00102: Capture of dusts from hypervelocity collision of planetary materials: Implication for dust size distribution in debris discs Susumu Takasawa, Akiko Nakamura, Toshihiko Kadono, Masahiko Arakawa, Hirotsugu Dohi, Yusuke Seto, Makoto Maeda, Keisuke Shigemori, Yoichiro Hironaka, Tatsuhiro Sakaiya, Takayoshi Sano, Takeshi Watari, Shinsuke Fujioka, Sohsuke Ohno, Taku Takeuchi, Kazuyoshi Sangen In order to examine the size distribution of dust particles from collision of solid bodies, we conducted hypervelocity impact experiments. Sub-mm size metal spheres were accelerated to velocities from 9 to 61 km/s by laser ablation and were shot into rock targets. Dust particles were collected by aerogels and were analyzed by Electron Probe Micro Analyzer (EPMA). We derived the size distributions of ejecta ranging from five to tens of micron in diameter. The slope of cumulative ejecta size distribution was steeper than a purely collisional equilibrium distribution in a collision cascade. This suggests that a steep dust size distribution in a debris disc around an A5V star HD172555 can be due to a hypervelocity impact. [Preview Abstract] |
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F1.00103: A New Semi-Analytical On-Hugoniot EOS of Materials with Known Shock Velocity Parameters Seiji Sugita, Kosuke Kurosawa, Toshihiko Kadono Accurate equation of state (EOS) is essential for understanding a variety of geologic processes associated with shock compression of materials. A number of highly sophisticated EOS's have been proposed (e.g., MANEOS and SESAME), covering a wide range of P-T conditions. However, they are complex and require many model parameters. Also, there are many occasions when only terminal thermodynamic variables after adiabatic decompression are needed. For example, when the terminal molecular composition of an impact-induced vapor is necessary, only the initial entropy gain and chemical reaction processes under low-P-T conditions need to be calculated. Then, only an on-Hugoniot EOS and a low-P-T EOS are necessary. To meet such demand, we derive a new semi-analytical on-Hugoniot EOS, which requires only the Hugoniot shock velocity parameters and specific heat. Comparison with experimental data indicates that this EOS can reproduce on-Hugoniot entropy and temperature of ice and quartz very well, despite of its small number of model parameters. Our new EOS will be useful for studying chemical reactions in shock-induced vapor plumes. [Preview Abstract] |
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F1.00104: Metallic GGG at TPa pressure Marius Millot, Suzanne Ali, Raymond Jeanloz, Maria Barrios, Tom Boehly, Jon Eggert, Gilbert Collins The Gadolinium Gallium Garnet (GGG) Gd$_{3}$Ga$_{5}$O$_{12}$ has attracted a strong interest since Gas gun shock wave experiments unraveled a high pressure phase stiffer than diamond in the 100 GPa to 250 GPa range [Mashimo], recently confirmed by DAC static compression experiments up to 180 GPa [Mao]. The quasi uncompressible phase has been found to remain much more insulating than metallic fluid Hydrogen and appeared as a potential perfect anvil for off-Hugoniot Hydrogen shock compression to very high density. We have conducted laser driven shock experiments on GGG and determined the EoS through using velocimetry (VISAR) and pyrometry (SOP) diagnostics and an impedance match analysis with quartz standards at Omega-LLE and Jupiter-LLNL facilities. We have observed metallic reflectivity in GGG from $\sim $200 GPa to $\sim $2500 GPa. However, GGG is found to remain highly incompressible in this very high density and temperature range. References: [Mashimo] Mashimo et al., \textit{Transition to a Virtually Incompressible Oxide Phase at a Shock Pressure of 120 GPa (1.2 Mbar): Gd3Ga5O12,} PRL 96, 105504 (2006) [Mao] Mao et al\textit{., Equation of state of a high-pressure phase of Gd3Ga5O12}, PRB in press [Preview Abstract] |
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F1.00105: HIGH ENERGY DENSITY PHYSICS/WARM DENSE MATTER |
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F1.00106: Cylindrical Compression of Gases using Pulsed Power Guy Burdiak, Sergey Lebedev, Simon Bland, Lee Suttle, Adam Harvey-Thompson, George Swadling, Philip de Grouchy, Louisa Pickworth, Essa Khoory, Gareth Hall, Francisco Suzuki-Vidal, Jonathan Skidmore The first experiments aimed at shock compressing high Z gas in a converging cylindrical geometry have been carried out on the MAGPIE generator (1.4 MA, 250 ns rise). A thin walled tube or liner (approx. 50$\mu$m wall, 10mm diameter) is filled with argon at a few mBar and subjected to the MAGPIE current pulse. Material ablated from the inner liner surface is accelerated towards the axis by the JxB force and acts on the gas inside. Experiments with no gas fill show an initially azimuthally symmetric plasma flow from the inner liner surface with a velocity of 100-150km/s. Axial laser probing and self-emission data are presented for these experiments, along with preliminary gas-fill results. [Preview Abstract] |
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F1.00107: X-ray Thomson scattering of warm dense matter on the Z-Accelerator Tommy Ao, James E. Bailey, Eric C. Harding, Michael P. Desjarlais, Stephanie B. Hansen, Marcus D. Knudson, Raymond W. Lemke, L. Paul Mix, Daniel B. Sinars, David F. Wenger, P. David Lepell, Gianluca Gregori Accurate measurements of warm dense matter (WDM) physical properties, such as temperature, density, and ionization state, are important for understanding and modeling high-energy density physics. X-ray Thomson scattering has recently been used to probe WDM states generated with high-power lasers. The Z-Accelerator has the capability to create WDM states with greater uniformity, larger size, and longer duration than that achievable on laser-driven experiments. Magnetically launched flyers experiments on the Z-Accelerator utilizing the Z-Backlighter Laser to generate x-rays for scattering of shock-compressed samples are in preparation. A new spherically bent focusing spectrometer has been built to measure scattered x-rays with high spatial and spectral resolution, and high sensitivity. Initial calibration measurements and plans for future Z experiments will be discussed. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. [Preview Abstract] |
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F1.00108: ABSTRACT WITHDRAWN |
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F1.00109: Pulsed power driven radiative shockwaves Jonathan Skidmore, Simon Bland, Sergey Lebedev, Francisco Suzuki-Vidal, Gareth Hall, Matteo Bocchi, George Swadling, Jeremy Chittenden, Adam Harvey-Thompson, Louisa Pickworth, Guy Burdiak, Essa Khoory, Philip De Grouchy, Lee Suttle A method of tailoring pulsed power driven radiative shock waves is discussed and preliminary data presented. A radial plastic disk coated in a thin film of Aluminium was held between two co-axial electrodes inside a gas cell filled with a high Z gas. The current path produced a toroidal magnetic field around the central cathode. As the current flowed from the cathode and onto the foil surface it became radial and due to the increase in area across the foil there was an inherent decrease in the current density. A shock was formed as a result of Ohmic heating (dependent on J(r)) or magnetic forces (dependent on B) such as the Lorentz force. The shock was conical in form; it was estimated to have a velocity of 60km/s and a post shock temperature of approximately 8eV. Results are compared to 3D resistive MHD code simulations. Initial attempts at planar and convergent shock geometries are presented. [Preview Abstract] |
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F1.00110: EXAFS measurements of compressed Fe at earth core conditions Yuan Ping, Damien Hicks, Barukh Yaakobi, Tom Boehly, Dayne Fratanduono, Sebastien Hamel, Ryan Rygg, Jon Eggert, Ray Smith, Rip Collins Properties of iron at earth core conditions are of primary interest in geophysics, geochemistry and seismology. These off-Hugoniot states can be created by dynamic multi-shock compression. We have performed EXAFS (extended x-ray absorption fine structure) measurements on Fe up to 3.5Mbar using OMEGA laser. Results of single-shock and multi-shock compression will be presented. Comparison between data and QMD simulations will be discussed. [Preview Abstract] |
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F1.00111: Experimental study and application of shaped pulse laser-driven compression waves Xiuguang Huang, Sizu Fu, Hua Shu, Junjian Ye, Zhiheng Fang, Guo Jia, Zhiyong Xie, Huazhen Zhou In this paper, a new target configuration and compression technique is described, which is used to ramp (or quasi-isentropic) compression aluminum to pressures of tens GPa. At the same time, measurements of velocities from shock front in quartz irradiating by two 120-ps pulses separated by 1-2ns are presented. These pulses drive two shocks that coalesce in the target, and the shock front propagation velocity histories, coalescence times, and transit times are unambiguously observed using VISAR. Moreover, some phenomena, which appeared in the experiments, are discussed and analyzed. [Preview Abstract] |
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F1.00112: Simulation of Laser Interaction with Ablative Plasma and ydrodynamic of Laser Supported Plasma(LSP) Tong Huifeng, Tang Zhiping A general Godunov finite difference schemes-WENO(Weighted Essentially Non-Oscillatory) Schemes which have fifth-order accuracy was used to make a numerical calculation for 2-dimensional axis symmetrical laser-supported plasma flow field under laser ablated solid target. The models of the calculation of ionization degree of plasma and the interaction between laser beam and plasma and the simplified eos(equation of state) of plasma were considered in the simulation. The plasma field parameters during and after laser duration variation with time are also obtained. The simulation results show that the laser beam power was strong absorbed by plasma of target surface, and the velocity of LSD(Laser Supported Detonation) wave is half of ideal LSD value which derived from C-J detonation theory. [Preview Abstract] |
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F1.00113: INELASTIC DEFORMATION, FRACTURE, AND SPALL |
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F1.00114: Analysis on the spall damage in ductile materials under dynamic loading Fengguo Zhang, Hongqiang Zhou, Jianli Shao, Guangcai Zhang, Tao Hong A statistical model of dynamic damage by void nucleation, growth is proposed for ductile materials sustaining intense loading. The model accounts for the early growth of void and their interaction. The computer simulations of spall experiments for copper, based on the proposed model, are performed with the finite element method. The computed results for free surface velocity profile and void concentrations through the thickness is in good agreement with experimental data. The early growth of voids and the correlation of the damage evolution and the stress history near the spall plane are analyzed, Besides, the contributions of different size voids to porosity are explored. [Preview Abstract] |
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F1.00115: Dynamic Fracture Behavior of Plastic-Bonded Explosives Hua Fu, Jun-ling Li, Duo-wang Tan Plastic-Bonded Explosives (PBX) are used as important energetic materials in nuclear or conventional weapons. Arms Warhead in the service process and the ballistic phase, may experience complex process such as long pulse and higher loading , compresson, tension and reciprocating compression - tension, friction with the projectile shell, which would lead to explosive deformation and fracture.And the dynamic deformation and fracture behavior of PBX subsequently affect reaction characteristics and initiation mechanism in explosives, then having influence on explosives safety. The dynamic fracure behavior of PBX are generally complex and not well studied or understood. In this paper, the dynamic fracture of explosives are conducted using a Kolsky bar.The Brazilian test, also known as a indirect tensile test or splitting test , is chosen as the test method. Tensile strength under different strain rates are obtained using quartz crystal embedded in rod end. The dynamic deformation and fracture process are captured in real-time by high-speed digital camera, and the displacement and strain fields distribution before specimen fracture are obtained by digital correlation method. Considering the non-uniform microstructure of explosives,the dynamic fracture behavior of explosive are simulated by discrete element method, the simulation results can reproduce the deformation and fracture process in Brazilian test using a maximum tensile strain criterion. [Preview Abstract] |
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F1.00116: Interpretation of pull-back signals at incipient spall in pure aluminum using unit cell model Y.G. Wang, M.L. Qi, H.L. He Planar impact spall experiments of pure aluminum have been preformed with the different impact velocities ranging from 196 to 236 m/s, which is necessary to induce the incipient spall conditions. Both velocity profiles at the rear surface and optical metallographic of soft-recovered samples are obtained. In order to reveal the physical mechanism of pull-back signals at incipient spall, numerical investigations with the FE commercial code LS-DYNA have been carried out using a simple unit cell model to describe the damage evolution. The simulated free surface velocity profiles and relative void volume for different impact velocities are in very good agreement with the experimental data. By analyzing stress decay in the matrix surrounding the growing voids, it is validated that the occurrence of pull-back signals is due to the influence of damage kinetics on wave dynamics. Meanwhile, the dependence of the amplitude of the pull-back velocity on damage is explored. [Preview Abstract] |
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F1.00117: Effects of Grain distribution anisotropic on dynamic damage of ultrapure aluminum Meilan Qi, Chao Luo, Duan Fan, Sheng Zhong, Hongliang He Based on Velocity Interferometer System for Any Reflector (VISAR) and ``soft-recovered'' technique of samples, incomplete spall experiments have been conducted for two groups of samples from the same ultrapure aluminum rod but different cutting direction. The sample cut from the direction parallel to the axis is called ``longitudinal-cutting sample'' and the sample cut from the direction perpendicular to the axis is called ``cross-cutting sample.'' By comparing the free surface velocity profile and damage of two groups of samples, the vast discrepancies in the two groups of samples have been discussed in detail. For the samples in a group, the pullback velocity changes very small with increasing impact pressure when samples spall incompletely. But for the samples in different groups, the pullback velocity has difference of 39 m /s with the same impact pressure. Moreover, there are the same damage distribution trends in the same groups of samples, such as voids will coalescence along to the impact direction in the cross-cutting samples. But there are large damage distribution discrepancies in the different groups of samples with the same impact pressure. [Preview Abstract] |
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F1.00118: Shock Response and Structure Of Yttria-Doped Tetragonal Zirconia Vladimir Milyavskiy, Andrey Savinykh, Felix Akopov, Leonora Borovkova, Georgy Valiano, Tatiana Borodina, Evgeny Lukin, Nelia Popova, Vadim Ziborov A new technology of ceramics manufacturing is proposed. The technology is based on zirconium dioxide, partially stabilized by yttria, obtained by a heterophased chemical deposition method. The main properties of the manufactured ceramics have been characterized by us: density of 5.79 g$*cm^{-3}$, bending strength of $\sim$800 MPa, crack resistance of $\sim$8 MPa$*m^{0.5}$, microhardness of $\sim$15 GPa. The microstructure and phase composition have been also investigated. The average size of sintered ceramic grains was 0.6 micron. It was established that the ceramics consisted of 93 mass \% tetragonal and 7 mass \% monoclinic phase and had X-ray density of 6.18 g$*cm^{-3}$. We have obtained longitudinal and transversal sonic speed relation to the frequency range of 1.25 -- 10 MHz. The measurements have shown dispersion occurrence. At dynamic loading the PSZD ceramics had shown high efficiency in Hugoniot elastic limit and spall strength. [Preview Abstract] |
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F1.00119: Failure of Metallic-Intermetallic Laminate Composites under Dynamic Loading Sergey Zelepugin, Vyacheslav Mali, Aleksej Zelepugin, Elena Ilina New approach to manufacture the metallic-intermetallic laminate (MIL) composites is realized: explosion welding of a package of titanium and aluminum sheets with the subsequent sintering without a hydraulic press. Sheets of the titanium (thickness of 0.5 and 0.6 mm), aluminum (thickness of 1.0 mm) are used. Packages with 11, 13 and 21 alternating Ti-Al layers in the sizes 50-120 and 120-300 mm are received. The processes of high-velocity interaction of a projectile with the MIL composite target were numerically investigated in axisymmetrical statement using modified finite element method. Results of computations demonstrate that a uniform target entirely from both Al$_{3}$Ti and Ti-6-4, has less ballistic resistance in comparison with the composite one. Optimum construction of the composite target should include metal layer of sufficient thickness, which should provide the termination of propagation of brittle cracks. [Preview Abstract] |
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F1.00120: Microstructural evolution in void coalescence induced by plate-impact loading in ultrapure aluminum Duan Fan, Chao Luo, Mei-lan Qi, Xiao-liang Deng, Hong-liang He, Wen-jun Zhu, Fu-qian Jing Under dynamic tensile loading, Spallation damage results from the nucleation, growth and coalescence of voids in a ductile metal. Microvoid nucleation is the major damage process of damage evolution. The microstructures of microvoid, which result from dynamic tensile loading in high pure aluminum 99.999{\%}, were characterized by a transmission electron microscope (TEM) and a high-resolution TEM. It was found that there may be a new nucleation mechanism of damage evolution in a ductile metal, which might be called melt nucleation. During shock compression, shock energy gives rise to local melting in high pure aluminum, and then a new free surface is generated under the tensile stress in the melting areas. Nanocrystalline amorphous metal is produced by rapid quenching a molten aluminum. In our experimental observations, the grain size of Nanocrystalline amorphous aluminum is 5-20 nm. This will increase understanding of the physical processes of dynamic tensile fracture of materials under high strain rate deformation. [Preview Abstract] |
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F1.00121: Calibrating Strain Rate Dependence of Viscoplastic Flow from Fourth Power Law Data Yehuda Partom The standard way of parametrizing a steady structured shock is by plotting the stress jump across the wave ($\Delta \sigma )$ versus its maximum strain rate ($\dot {\varepsilon })$ on a logarithmic plot. Doing so one usually gets a straight line, which means that$\dot {\varepsilon }\propto \left( {\Delta \sigma } \right)^\beta $. Grady and coworkers noticed in the 1980s that for many materials $\beta $=4. Since then several workers in the field tried to understand this unusual behavior, but no satisfactory explanation was found. Recently Grady revisited the fourth power law with an extensive review, including descriptions of the various mechanisms proposed as possible explanations. In view of this background we use here the fourth power law to calibrate the strain rate component of the constitutive response of Al 6061-T6. To this end we integrate the steady viscoplastic equations (developed long ago) from the elastic precursor level to the stress plateau level. We find that the plastic deformation rate has to depend on the deviator overstress by $\dot {d}^p\propto \left( {s-\textstyle{2 \over 3}Y} \right)^\alpha $ with $\alpha $=2.38. But for high shock levels, when the elastic precursor is overdriven, using this value of $\alpha $ leads to a higher value of the slope $\beta $, close to $\beta $=6. [Preview Abstract] |
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F1.00122: Influence of complex stress state on spall fracture in high-purity copper Xiaoyang Pei, Changming Hu, Meilan Qi, Hongliang He, Ping Li Consideration is given to non-one-dimensional shock wave on damage and spallation of high-purity copper. The creation of damaged regions leading to failure are conducted in gas-gun experiments using a smaller flyer plate (diameter $\sim$ 50mm) impacting a larger target plate (diameter $\sim$ 100mm). Because of the edge rarefaction effect, non-planer waves originating from the circumferential edge complicate the pattern of wave deformation. A multi-Doppler Pin Systems (DPS) were used to detect the free surface velocities of variable points. The damage and post-shock microstructures of the soft recovered samples were characterized using metallogenetic microscopy. The experiments were simulated with a two-dimensional finite-element calculations employing a damage function model. The peak stress, peak tensile stress and wave shape of different radial locations are determined by the comparisons of experiment and simulation results of free surface velocity profiles. Damage evolution processes and localized behavior of different locations in sample were studied. It was concluded that the shock-wave profile shape and the stress/strain state both strongly affect the spall properties and damage distributions. [Preview Abstract] |
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F1.00123: NON-Shock-Plasticity/Fracture Burst Acoustic-Emission(BAE) ``1''/f -``Noise'' Power-Spectrum Power-Law UNIVERSALITY is Merely F=ma Time-Series Integral-Transform, aka ``Bak'' -``SOC'' REdiscovery'' PRE(1687)-"Bak"(1988) Edward Siegel, Frank Nabarro, Alan Brailsford, Clement Tatro NON-shock-plasticity/fracture BAE[E.S.:MSE 8,310(71);PSS:(a)5,601/607(71);Xl.-Latt. Defects 5,277(74);Scripta Met.:6,785(72); 8,587/617(74);3rd Tokyo AE Symp.(76);Acta Met. 25,383(77);JMMM 7,312(78)] ``1''/$\omega $-``noise'' power-spectrum ``pink''-Zipf-(NOT ``red''-Pareto) power-law UNIVERSALITY is manifestly-demonstrated in two distinct ways to be nothing but Newton Law of Motion F = ma REdiscovery!!!(aka ``Bak''(1988)-``SOC'':1687 $<<<$1988: 1988-1687=301-years!!! PHYSICS:(1687) cross-multiplied F=ma rewritten as 1/m=a/F=OUTPUT/IN-PUT=EFFECT/CAUSE=inverse-mass mechanical-susceptibility=X("$\omega $"); X("$\omega $ ")$\sim $(F.-D. thm.) $\sim $P("$\omega $") "noise" power-spectrum; (``Max {\&} Al show''): E$\sim \omega $ , {\&} E$\sim $(or any/all media with upper-limiting-speeds)$\sim $m. Thus: $\omega \sim $E$\sim $m; inverting: 1/$\omega \sim $1/E$\sim $1/m$\sim $a/F= X("$\omega $")$\sim $ P("$\omega $"); thus: F=ma integral-transform(I-T) is "'SOC"'s" P($\omega )\sim $1/$\omega $ !!! ; "PURE"-MATHS: F=ma DOUBLE-integral time-series(T-S) s(t)=[v$_{0}$t+(1/2)at$^{2}$] I-T formally defines power-spectrum: [Preview Abstract] |
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F1.00124: SHOCKS Impulse-Jerk(I-J) Plasticity/Fracture Burst Acoustic-Emission(BAE) NON:``1''/$\omega $ -``Noise''; Power-Law; Universality Power-Spectrum is I-J Time-Series Fourier-Transform: 1687 $<<<$ 1988: VERY-LONG PRE-"Bak"!!! Aldo Chavira, Victor Gregson Jr., Sidney Green, Edward Siegel SHOCKS impulse-jerk(I-J) [apply strain/impulse to get stress/jerk ],{\{}VS. NON-shocks[apply stress to get strain]{\}}, plasticity/fracture BAE[E. S.: MSE 8.,310(71); PSS: (a) 5, 601/607(71); Xl..-Latt. Defects 5, 277(74); Scripta Met.: 6, 785(72); 8, 587/617(74); 3$^{rd}$ Tokyo A.-E. Symp. (76);Acta Met.25,383(77); JMMM 7, 312(78)] NON: ``1''/$\omega $ -``Noise''; Zipf(NON-Pareto); power-law ; universality power-spectrum is manifestly-demonstrated in ONLY ``PURE''-MATHS way to be nothing but d[F(t)=m(t)a(t)=Newton's (3$^{rd})$ Law of Motion=(I-J)]/dt I-Jderivative d(I-J)/dt=dF(t)/dt=[m(t)da(t)/dt+a(t)dm(t)/dt] REdiscovery!!! A/Siegel NON-shock PHYSICS derivation fails!!!; "PURE"-MATHS: dF(t)/dt=d$^{2}$p(t)/dt$^{2}$=[m(t)da(t)/dt+a(t)dm(t)/dt] TRIPLE-integral [VS. NON -shocks F = ma time-series DOUBLE-integral] Dichotomy: s(t) = [v$_{0}$+(1/2)a(t)t$^{2}$+EXTRA-TERM(S)], {\{}VS. s(t) = [v$_{0}$t+(1/2) at$^{2}$]{\}}, integral-transform formally defines power-spectrum Dichotomy: [Preview Abstract] |
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F1.00125: Threshold for dynamic re-crystallization in shock loaded aluminum alloy Yury Meshcheryakov, A.K. Divakov, N.I. Zhigacheva, I.P. Makarevich, B.K. Barakhtin Shock loading of D16 aluminum alloy within impact velocity range of 30-450 m/s reveals two regimes of dynamic deformation. Three dynamic variables -- particle velocity $U_{p}$, particle velocity dispersion $D^{2}$ and velocity deficit at the plateau of compressive pulse \textit{$\Delta $U} are registered in real time at every shock. At the impact velocities lower 380 m/s, velocity deficit (which quantitatively characterizes an intensity of meso-macro energy exchange) is very small or absent at all. In this region of impact velocities the structure of material remains invariable. At 380 m/s a catastrophical growth of velocity deficit occurs, which corresponds to start of dynamic re-crystallization process as adaptation mechanism to loss of structural stability of dynamically deformed material. The size of grains decreases from 30 $\mu $m to 1,5 -2 $\mu $m. The catastrophical growth of velocity deficit happens when rate of change of velocity dispersion becomes higher than rate of change of mean particle velocity, i.e. a criterion$\left( {\frac{D}{u}\frac{\dot {D}}{\dot {u}}} \right)\ge 1$ is fulfilled. [Preview Abstract] |
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F1.00126: ROTATIONAL- SHOCK(S) Impulse-Jerk(I-J) [VS. T=I$\alpha $] Plasticity/Fracture Burst Acoustic-Emission(BAE) NON: ``1''/[f=$\omega $]-``Noise''; Power-Law Power-Spectrum is T=I$\alpha $ DERIVATIVE I-J Time-Series Integral-Transform Thomas Lewis, Edward Siegel ROTATIONAL-[``spin-up''/``spin-down'']-SHOCK(S)-plasticity/fracture BAE[E.S.:MSE 8,310(71); PSS:(a)5,601 /607(71); Xl..-Latt. Defects 5,277(74);Scripta Met.:6,785(72);8,587/617(74);3$^{rd}$ Tokyo A.-E. Symp.(76);Acta Met. 25,383(77);JMMM 7,312(78)] NON: ``1''/$\omega $ noise''; Zipf-(Pareto); power-law universality power-spectrum; is manifestly-demonstrated in two distinct ways to be nothing but ROTATIONAL(in 2 OR 3-dimensions)ANGULAR-momentum Newton's 3$^{rd}$ Law of Motion T=I$\alpha $=dJ/dt REdiscovery!!! A/Siegel PHYSICS derivation FAILS!!! "PURE"-MATHS: dT(t)/dt=(dJ(t)/dt)$^{2}$=[I(t)d$\alpha $(t)/dt+$\alpha $(t)(t)dI(t)/dt TRIPLE-integral VS. T=I$\alpha $ DOUBLE-integral time-series(T-S) Dichotomy: $\theta $(t)=[$\varpi _{0}$t+$\alpha $(t)t$^{2}$/2+EXTRA-TERM(S)] VS. $\theta $(t)=[$\varpi _{0}$t+$\alpha $(t)t$^{2}$/2] integral-transform formally defines power-spectrum Dichotomy: P($\omega )$=?$\theta $(t)e$^{-i\omega t}$dt=?[$\varpi _{0}$t+$\alpha $t$^{2}$/2]e$^{-i\omega t}$dt=$\varpi _{0}$?te$^{-i\omega t}$dt+?{\{}[$\alpha \ne \alpha $(t)]/2{\}}t$^{2}$e$^{i\omega t}$dt= $\varpi _{0}$ ($\omega )$/d$\omega $+{\{}[a$\ne $a(t)]/2{\}}d$^{2}\delta (\omega )$/d$\omega ^{2}=\varpi _{0}$/$\omega ^{0}$+{\{}[$\alpha \ne \alpha $(t)]/2{\}}/$\omega ^{1.000\ldots }$: if $\alpha $=0, then P($\omega )\sim $1/$\omega ^{0}$, VS. if $\alpha \ne \alpha $(t)$\ne $0, then P($\omega )\sim $1/$\omega \sim $1/$\omega ^{1.000\ldots }$ [Preview Abstract] |
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F1.00127: SHOCKS-``COMPLICATEDNESS'' Impulse-Jerk (I-J): [a(t)];[m(t)] DEVIATIONS FROM/VS. "(so MIScalled) `Complexity' as UTTER-SIMPLICITY!!!''(``SMCIUS!!!''): SHOCKS Burst Acoustic-Emission(BAE) ``COMPLICATEDNESS''-MEASURE(S) Frederick Young, Edward Siegel (so MIScalled) "complexity" associated BOTH [SCALE-Invarience Symmetry-RESTORING] AND X(w) $\sim $(F-D-thm.)$\sim $ P($\omega )\sim $''1''/$\omega \sim $``1''/$\omega ^{1.000\ldots }$ "pink" Zipf-law Archimedes-HYPERBOLICITY INEVITABILITY BAE power-spectrum power-law decay algebraicity (or at least "red" Pareto-law~ X($\omega )\sim $(F.-D.-thm.)$\sim $P($\omega )\sim $1/$\omega ^{(0 < \# \ne 1.000\ldots )})$.~Their INTERCONNECT-ION? Simple-calculus [SCALE-Invariance Symmetry-RESTORING(S-I S-R)] LOGARITHM-function derivative: d ln($\omega )$/ d$\omega $= hence: d[S-I S-R]($\omega )$/d$\omega $= ; via Noether-theorem continuous-symmetries relation to conservation-laws is: [d[{\{}inter-scale 4-current 4-divergence{\}}/d$\omega =\sum _{\mu }\partial ^{\mu }$J$_{\mu }$=0]($\omega )$=1/. Hence (so MIScalled) "complexity" is~inter-scale information-conservation(nano to meso to macro)[in amazing exact agreement with Anderson-Mandell-Selz[PhD, FAU(91); Fractals of Brain/Mind, G. Stamov ed.(94)]; experimental-psychology!!!], i.e.~``SMCIUS!!!'' VS. SHOCKS-"COMPLICATEDNESS" NON: ``1''/$\omega $ Zipf/(Pareto?); power-law; algebraicity; universality power-spectrum inverse-transform of time-series of shock's impulse-jerk(I-J) [Preview Abstract] |
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F1.00128: Temperature dependence of spall strength of magnesium alloy over the 90--750 K temperature range Svetlana Malugina, Dmitry Kazakov, Mikhail Serkov, Vyacheslav Bychkov The paper presents results of investigations aimed to determine how spall strength of the MA14T1 magnesium alloy depends on temperature. These investigations were performed with the help of the one stage gas gun and the impact method. The stress wave profiles were measured by the two-channel push-pull VISAR in one speed range of loading (impact velocity approx. 345 m/s). The data on the shape and amplitude of the elastic precursor was also obtained. The temperature dependence of spall strength was obtained for temperatures ranging from -- 90 to 750 K. The impactor thickness was 3 mm, and that of the sample -- 6 mm. [Preview Abstract] |
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F1.00129: SHOCKS Fast-Fracture Periodic-Intermittency VS. Random-Sporadicity in Burst Acoustic-Emission (BAE): Dislocation-Line-Defects Special-Relativity Classical Acoustic-Phonon Maser(CAPM) EDDTA Orgins of ``Bak''-``SOC'' Peter Neumann, Yuri Klimontovich, Frank Nabarro, Alan Brailsford, Edward Siegel Glassy fast-fracture instabilities and patterns, long-known semi-infinite crack-propagation sub-terminal-velocity Rayleigh-wave-speed versus ``2''-D linear-elasticity theory predictions, but rather asymptotic to maximum-speed $<$ 0.6 v(Rayleigh), explicitly experimentally identifies a fast-fracture DYNAMIC-instability(FFDI) not included within fracture linear-elasticity theory. FFDI causes PERIODIC-BAE[E. S.:MSE 8.310(71); PSS:(a) 5, 601/ 607 (71); Xl..-Latt. Defects 5, 277(74);Scripta-Met.:6,785(72);8, 587/617(74); 3rd Tokyo A.-E. Symp. (76); Acta- Met.25,383(77); JMMM 7,312(78); $\ldots$] emitted/radiated from advancing-crack in addition to crack-velocity fluctuations causing such low sub-Rayleigh crack-velocities, hinting at dimensionality-dominance in 2-D VS. 3-D lattice-``models'' very-provacatively yet another special-case subset of Siegel[MRS Fall-Mtg.,Boston:Symp. On Fractals(89)-5-papers!!!; Symp. On Scaling(90)] SPD/FUZZYICS. Hirth-Lothe-Nabarro-Weertman-… provocative finite Burgers-vector dislocations/line-defects singularities terminal-velocity special-case of Einstein's special-relativity, almost word-for-word Jackson electromagnetics, replaces light-speed by sound-speed!!! Siegel[ 3rd Tokyo A.-E. Symp.(76); Intl.Quantum-Electronics Conf., Boston (80)] [Preview Abstract] |
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F1.00130: "Super"alloys GENERIC ENDEMIC EXTANT THERMAL Wigner's-Disease/.../Overageing-Embrittlement/ ``Sensitization'' SEVERE SHOCKS-INstability; Siegel FIRST ORIGINAL EXPERIMENTAL Giant-Magneto-resistance(GMR) Diagnosis Aziz Asphahani, Clement Tatro, Wendell Williams, Thomas Lewis, Ace Hoffman, Albart Fart, Peter Gruntbug, Edward Siegel Carbides solid-state chemistry[ES {\&} WW: PSS (72); Semis. {\&} Insuls.(79)-3-papers!!!] domination~of old/new nuclear-reactors/spent-fuel-casks/refineries/jet/ missile/rocket-engines in austenitic/FCC Ni/Fe/Co-based (so mis-called) "super"alloys(182/82;Hastelloy-X,600,304/304L-Stainless-Steels,...690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms!!!): THERMAL: Wigner's-disease(WD;physics)[J.Appl.Phys.17,857(46)]/ Ostwald-ripening (OR;chemistry)/spinodal-decomposition(SD;physics)/overageing- [Preview Abstract] |
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F1.00131: Meso-macro momentum exchange and steady-wave propagation Yury Meshcheryakov Mechanism of meso-macro momentum exchange is incorporated into steady-wave shock solution grounded on the dislocation dynamics. As a test task, propagation of steady plastic front is considered and analytical solution for particle velocity is obtained. Experimental particle velocity profiles of Johnson and Barker for 6061-T6 aluminum alloy and D16 aluminum alloy are used for comparison with the theoretical profiles. Including the meso-macro momentum exchange into constitutive equation allows to fit experimental velocity profiles without increasing the initial dislocation density. [Preview Abstract] |
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F1.00132: Dynamic properties of bulk metallic glass on the base of Zr Ivan Smirnov, Svetlana Atroshenko, Yuri Sudenkov, Nikita Morozov, Wei Zheng, Natalia Naumova, Jun Shen The high-strain-rate methods of materials were developed for dynamic strength investigations under micro- and sub-microsecond durations of shock loads on the base of electrical explosion of conductors. The experimental investigations of dynamic properties for bulk metallic glasses on the base of Ti and Zr under shock loads of sub-microsecond duration $\sim $( 0.5-0.7) $\mu $s in the pressure range up to 12GPa were carried out. The values of HEL and spall strength for these amorphous alloys were received. The Hugoniot shock adiabat parameters were determined in the space U$_{sh}$-u$_{p}$. The results of microstructure analysis of saved specimens revealed essential differences in deformation mechanisms determining plastic flow in these alloys under high-strain-rate. [Preview Abstract] |
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F1.00133: Modeling of constructional elements fragmentation:3-D statement and probabilistic approach Alexander Gerasimov, Sergey Pashkov The heterogeneity of real materials structure influencing on distribution of material characteristics is one of the factors determining a destruction character. The introduction of the given factor in the equations of mechanics of deformed solid is possible at the use of probabilistic laws of characteristics distribution in the volume of a considered design. The explosive fragmentation of the open and closed shells, thick plate punching by HE charged shell on a normal and at an angle, plate and a shell fragmentation after plate piercing and under HE charge explosion, thin barrier punching on a normal and at an angle, crushing of metal rings dressed on a copper tube, process of high-speed impact of laminated-spaced metallic plates with steel spheres modeling debris of space bodies and artificial objects are considered. The processes are calculated in view of material heterogeneity. To calculate elastoplastic flows and detonation products we used the technique realized on tetrahedral cells and based on Wilkins method for calculation of internal points of a body and on Johnson method for calculation of contact interactions. [Preview Abstract] |
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F1.00134: Numerical simulations of fracture processes in experiments with shock-loaded samples Maksim Anoshin, Lilia Gabzetdinova, Sergey Kuratov, Sergey Sokolov, Ekaterina Shuvalova, Yevgeny Kozlov, Vladimir Tarzhanov, Oleg Olkhov The paper presents the results of numerical simulations of fracture processes in experiments with shock-loaded wedge-shaped samples and with compressed steel spheres. The samples were compressed by a shock wave produced by a layer of condensed HE. The experiments were focused on the post-shot condition of the samples. The simulations were performed using DMK and LEGAK codes. The use of the NaG fracture model and other strength models is shown to enable the description of the basic features of experimental results. [Preview Abstract] |
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F1.00135: Evaluation of Five Fracture Models in Taylor Impact Fracture Wei Zhang, Xinke Xiao, Gang Wei, Zitao Guo Taylor impact test presented in a previous study on a commercial high strength and super hard aluminum alloy 7A04-T6 are numerically evaluated using the finite element code ABAQUS/Explicit. In the present study, the influence of fracture criterion in numerical simulations of the deformation and fracture behavior of Taylor rod has been studied. Included in the paper are a modified version of Johnson--Cook, the Cockcroft--Latham(C-L), the constant fracture strain, the maximum shear stress and the maximum principle stress fracture models. Model constants for each criterion are calibrated from material tests. The modified version of Johnson--Cook fracture criterion with the stress triaxiality cut off idea is found to give good prediction of the Taylor impact fracture behavior. However, this study will also show that the C-L fracture criterion where only one simple material test is required for calibration, is found to give reasonable predictions. Unfortunately, the other three criteria are not able to repeat the experimentally obtained fracture behavior. The study indicates that the stress triaxiality cut off idea is necessary to predict the Taylor impact fracture. [Preview Abstract] |
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F1.00136: Dynamic Behaviors of Lead Flyer Driven by Collision of Head-on Sliding Detonations Chongyu Zhang, Haibo Hu, Qingzhong Li, Zhengtao Zhang, Xuelin Sun The dynamic behaviors of lead plate driven by head-on sliding detonation waves were characterized with the help of high-speed frame photography and pulsed X-ray radiography. Experimental records have shown a jet like bulging in the collision region, size of which extended rapidly after the collision of the head-on detonation waves because of the obvious speed gradients of particles inside the bulging from the tip to the bottom of the bulging. Multi-layer like structure of loading front formed in the result of the impact of two symmetric detonation fronts. The mass densities inside the bulging structure fixed by the pulsed X-ray radiography were evaluated at the level of 1{\%}$\sim $10{\%} from the initial density of lead. The dynamic strength and shock wave melting should have played dominate role in the formation of the initial stage and the evolution of cavitations and fragmentation process finished merely in microseconds inside the continuum of melted lead under the intensive tension of release wave, in the result of which a porous or dispersed stage bulging was formed. [Preview Abstract] |
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F1.00137: The Generalized Courant-Friedrichs Equation of State for Condensed Matter Michael Grinfeld The (EOS) with separable internal energy play a big role in analysis of dynamics of deformable condensed matter [1]. For such models the internal energy density $E$, depending on the specific volume $V$ and entropy density $S$ can be presented in the form $E\left( {V,S} \right)=\Delta \left( V \right)+{\rm X}\left( S \right)$, where the 2 functions $\Delta \left( V \right)$ and ${\rm X}\left( S \right) \quad E\left( {V,S} \right)=\Delta \left( V \right)+{\rm X}\left( S \right)$ should be determined from experiment. We call this model the complete Courant-Friedrichs (CG) EOS. We suggest a generalized CF EOS depending on 3 functions and including the CF EOS as a special case. The additional degree of freedom permits us to take into account additional physical phenomenal, including inelastic ones. We discuss the interrelations between the newly introduced generalized CF EOS and several classical EOS, including the incomplete Mie-Gruneisen EOS (depending on 2 functions) and its complete extensions. It is also discussion how the 3 functions can be recovered from experimental data. \\[4pt] [1] R Courant, K.O. Friedrichs, Supersonic flow and shock waves, Interscience, New York, 1948. [Preview Abstract] |
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F1.00138: Specifics in plastic straining and spall fracturing of structural steel 12Cr18Ni10Ti Alexander Shestakov, Svetlana Malugina, Yury Zuev, Dmitry Kazakov, Dmitry Belyaev, Alexandr Grigoriev Interrelation between structure, chemical composition, and spall strength of steel 12Cr18Ni10Ti (close analog of the 304 stainless steel) was studied in shock-wave experiments. Push-pull VISAR measured the stress wave profiles and the spall pulse. The temperature dependence of spall strength was obtained for temperatures ranging from 300 to 730 K. Transverse microsections on recovered samples of steel 12Cr18Ni10Ti were examined by the SEM and optical microscopy method. Analysis of macrofracture distributions was used to analyze specifics in spall nucleation. The phase structural composition of recovered samples was investigated with the X-ray diffraction analysis. [Preview Abstract] |
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F1.00139: Exploring the temperature dependence of failure mechanisms in fragmenting metal cylinders David Jones, David Chapman, Paul Hazell, Simon Bland, Daniel Eakins We present current work to investigate the influence of temperature on the dynamic fragmentation of metals. Pre-heated/cooled cylinders of Ti-6Al-4V were subjected to rapid radial expansion up to and past the point of failure using a modified expanding insert method on a single stage gas gun. Additional experiments were performed using an electromagnetic drive system to produce uniform deformations on targets of differing dimensions (radius, wall thickness). Issues concerning the geometry of the experiments, methods of heating and cooling the sample and diagnostics are covered. Finally, the role of temperature on adiabatic shear banding and fragment distribution statistics is discussed. [Preview Abstract] |
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F1.00140: INELASTIC DEFORMATION, FRACTURE, AND SPALL: HIGH-PRESSURE STRENGTH |
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F1.00141: Growth of defining relations of beryllium Ignatova Olga, Raevsky Vicktor, Nadyozhin Sergey The paper presents the results for construction of defining relations of beryllium. The phenomenological elastic-plastic relaxation model is utilized to calculate the deviatoric component of a shear stress. A spherical component of stress tensor is expressed through the equation of state of state in the form of Mie-Gruneisen. Melting temperature dependence on density is determined on the basis of the equation of Lindeman. The model takes account of strain hardening and compression hardening, thermal softening, stress history, as well as relaxation of elastic stress. The parametric identification of equations was implemented based on the great number of experiments: static compression-tension diagrams, created at various temperatures; split-Hopkinson bar method; Taylor method; recording of free surface velocity via laser interferometer VISAR; method for recording of perturbations growth; method of principal stresses; measurements of shock wave thickness; measurements of shock-wave compressibility. [Preview Abstract] |
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F1.00142: Dynamic Strength of 304L stainless steel under impact Meir Werdiger, Lior Bakshi, Benny Glam, Shlomi Pistinner We use the Asay self consistent technique to analyze the effects of pressure hardening and strain hardening on SS304L. Previously unloading experiment has been used to infer the strength of this material at high pressure, and recently the Johnson-Cook (JC) model has been calibrated at low strain rate. Release and reshock experiments with impact velocity range of 300-1700 m/s were preformed. We used VISAR to extract the particle velocity of the SS304L- LiF window interface. The velocity profile compared to hydrodynamic simulation using JC model. Our unloading experiments have clearly demonstrate that the material yield but does not fail. Thus infer substantial effect of pressure hardening. [Preview Abstract] |
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F1.00143: High P-T Constitutive Properties and nanoMechanics Yusheng Zhao, Jainzhong Zhang, Xiaohui Yu, Yuejian Wang, Zhijun Lin Nano-crystalline materials show drastic differences in physical properties compared with their bulk counterparts under high pressure (P) and temperature (T) conditions. We show a model to explain the observed contrasts between nano-metals and nano-ceramics, in the sense that the surface tension and compression of nanocrystals are the underlying cause of the differences in elasticity, yield strength, and work hardening and weakening. This nano-mechanics model has been tested by the comparative study of constitutive property and elastic modulus of nano-/micron- crystalline materials under high pressure and high temperature conditions. These studies provide fundamental understanding for metal/ceramics performances at nano-scales. [Preview Abstract] |
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F1.00144: ABSTRACT HAS BEEN MOVED TO Y1.00006 |
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F1.00145: Semiempirical models of shear modulus at shock temperatures and pressures Vaytcheslav Elkin, Vadim Mikhaylov, Tatiana Mikhaylova The work is devoted to a comparison of capabilities the Steinberg-Cochran-Guinan and Burakovsky-Preston models of shear modulus offer for the description of experimental and calculated (ab initio) data at temperatures and pressures representative of solid state behind the shock front. Also, the SCG model is modernized by changing from the (P,V) variables to the (V,T) ones and adding a free parameter. The resulted model is then referred to as the (V,T)-model. The three models are tested for 9 metals (Al, Be, Cu, K, Na, Mg, Mo, W, Ta) with using ab initio and experimental values of shear modulus in a wide range of pressures as well as longitudinal sound velocities behind the shock front. [Preview Abstract] |
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F1.00146: Optical properties during elastic-plastic transition in Gd$_{3}$Ga$_{5}$O$_{12}$ single crystals under shock compression X. Zhou, W.J. Nellis, Jun Li, Jiabo Li, X. Liu, X. Cao, X. Wang, H. He, W. Zhu, Q. Wu Planar impact experiments were performed to investigate optical changes in high-impedance GGG single crystals during the elastic-plastic transition. Time-resolved radiance and transmission spectra were measured with a multi-wavelength pyrometer. Simultaneously, velocity profiles were diagnosed at the impact and free surfaces with a Doppler Pin System (similar to PDV). Findings include (1) pressure-dependent yielding in GGG with the HEL increasing from 7.65 to 24.2 GPa as final pressure increases from 8.52 to 88.5 GPa, (2) a unique feature of optical transparency lasts for some time, which is associated with elastic-stress relaxation and attributed to molecular bond breaking, (3) decay in spectral radiances emitted from plastically deformed GGG, based on which we propose a new model that takes light absorption and scattering into account. Our model reproduces observed radiance histories quite well. Initial transparency during the elastic process was verified by the optical transmission measurements at relevant low shock pressures ($<$62 GPa). [Preview Abstract] |
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F1.00147: Strength and formation of poor metals from insulators: bonds to bands in Al2O3 and H2 W.J. Nellis HELs of Al2O3 and H2 are $\sim $15 GPa and 0, respectively, while Al-O and H-H bond energies are both 4.5 eV and both are wide gap insulators at ambient. Al2O3 is a likely metallic glass at $\sim $300 GPa; hydrogen is a metallic fluid at 140 GPa. How can such different materials at ambient both be disordered poor metals at 100 GPas? As McQueen pointed out, shock dissipation TS is absorbed in temperature T and entropy S (disorder). Because of strength, the split between T and S differs greatly between these two. H2s interact via weak pair interactions, which means high compressibility, high shock Ts, and dissociation (S) to monatomic metal at high pressures. Al and O atoms interact strongly via directional bonds in large 3D networks. Dissipation is first absorbed breaking bonds (S), which keeps T and thermal pressure low up to 400 GPa. Once most Al-O bonds are broken, Al2O3 is amorphous and atom densities so large that atomic wave functions probably overlap to form a metallic glass. Existing conductivity measurements to 220 GPa need to be extended to $\sim $300 GPa to test this prediction. [Preview Abstract] |
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F1.00148: FIRST-PRINCIPLES AND MOLECULAR DYNAMICS CALCULATIONS |
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F1.00149: Molecular dynamic and kinetic study of carbon cluster aggregation in detonation products thermodynamic conditions. Guillaume Chevrot, Arnaud Sollier, Nicolas Pineau The detonation of carbon-rich explosives produces significant amounts of solid carbon residues that interact with the surrounding fluid mixture, modifying the equation of state of the detonation gas. The formation process of the solid carbon phase and its influence on the detonation products has been investigated for a decade through atomistic simulations and kinetic models but some questions remain about the coalescence mechanism and kinetics, in particular on the influence of the variation in thermodynamic properties during the gaseous product release. In this study, we present a combined molecular dynamics and kinetic study of the solid carbon clustering process in thermodynamic conditions relevant for the release of high explosive detonation products. First we use molecular dynamics simulations based on the LCBOPII potential to investigate the coalescence mechanism of nanocarbons under high temperature and pressure: under those conditions coalescence occurs whenever two carbon clusters approach to within the potential dispersion interaction range. Then we implement this statistical observation as well as various physically-based features to a Smoluchowski model to investigate the kinetics of aggregation of carbon, and draw qualitative comparisons with the available experimental observations. [Preview Abstract] |
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F1.00150: MD simulation of cavitation and formation of foam-like material inside the exploding wire Vasily Zhakhovsky, Sergey Pikuz, Tatiana Shelkovenko, Patrick Knapp, Charles Saylor, David Hammer, Svetlana Tkachenko, Pavel Sasorov Large-scale molecular-dynamics simulations of exploding aluminum and nickel wires with radii between 50 and 200 nm show that rapid Joule heating causes bulk melting and internal pressure build-up. A radial rarefaction wave propagates towards the center of the wire and increases in amplitude until stress inside the wave reaches the dynamic tensile strength of melt. At this point, cavitation starts within the wire and converges towards the center, resulting in the formation of a low-density foam-like material surrounded by a dense liquid cylindrical shell. As the wire expands further, this foam decays and yields liquid droplets, while the liquid shell survives for a considerably longer period of time. Mechanism of wire explosion obtained from MD simulations has been confirmed by hydrodynamic modeling and experimental data. Simulated spatial distributions of density demonstrate good qualitative agreement with hollow structures visible in high resolution X-ray radiography images. [Preview Abstract] |
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F1.00151: A new nickel EAM potential for atomistic simulations of ablation, spallation, and shock wave phenomena Brian Demaske, Vasily Zhakhovsky, Carter White, Ivan Oleynik A new embedded atom method (EAM) interatomic potential for nickel was developed with the goal to improve upon the predictive power of atomistic simulations of materials at extreme conditions. In contrast to standard approaches for the development of potentials, our methodology focused on accurate sampling of stress tensor components calculated in a wide range of isotropic and uniaxial compression and tensile strains. Also included in the fitting database were experimental properties at standard conditions, such as elastic constants, cohesion energy, vacancy formation, and stacking fault energies. In order to validate the new potential, the liquid-vapor coexistence line, melting line, and shock Hugoniot were calculated. In each case, the new EAM potential was found to be in good agreement with experiment. Preliminary results from simulations of ablation, spallation, and shock wave propagation will be discussed. [Preview Abstract] |
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F1.00152: Dynamical coupling atomistic and continuum simulations Guowu Ren, Dier Zhang, Xingao Gong Multiscale modeling makes simulations at large length and time scales feasible because of limiting capability of massively parallel computers. Here a dynamical multiscale method is implemented which couples the molecular dynamics method for atomistic region and atomic-based finite element method for continuum region, matching much better than conventional finite element method originating from linear elastic mechanics. As for spurious reflection induced by the coupled interface, a new damping method theoretically derived from filter principle is proposed, which dampens the reflection of high-frequency phonons while keeping the low-frequency phonons traveling. A serial of numerical simulations validate these schemes. [Preview Abstract] |
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F1.00153: Computational work minimization of two-bucket searches for meshless-particle neighbors Charles Gerlach Modeling explosive-solid interactions with meshless particles in a Lagrangian framework allows for robust computations in complex geometric situations where element explosives could be problematic. The EPIC code originally used a single-bucket scheme to find the nearby ``neighbor'' particles for the meshless algorithm. The efficiency of the bucketing scheme is O(N), where N is the number of particles, but there is a constant multiplicative factor which is proportional to the average number of particles per bucket (P). When the explosive particles expand, they can cause the bucket size to be an order of magnitude larger than what would be necessary for the majority of the particles, which drives up P and causes the computational time to become unworkably large. The computational time is reduced by adding a second set of buckets to sort the smaller particles. This paper will show the algorithm used to determine the size of the smaller buckets so as to approximately minimize computational time, and will also show some simulations that were made possible due to those time savings. [Preview Abstract] |
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F1.00154: Melting property of Mo at high pressure Zhang Gongmu, Liu Haifeng, Song Haifeng, Duan Suqing, Zhao Xiangeng DAC experiments showed Mo is stable in a bcc structure up to the pressure of at least 500 GPa at normal temperature . Shock wave experiment identified the first transition at 200GPa as that of bcc to a new solid phase(perhaps fcc). We conducted ab initio molecular dynamics simulations to reveal the effect of different solid structures for melting temperature. We use three methods: Z method, single phase method and two phase coexistence MD simulation, the simulations at different volumes and atoms arranged initially in an ideal bcc or fcc lattice. The Z method and two phase MD method can avoid superheating. The results show that the melting temperature of bcc solid is higher than fcc about 500K-1000K, the Z method and two phase MD simulation describe the two mechanisms (homogeneous and heterogeneous) of melting but with the same melt temperatures ,which are lower than single phase method about 10{\%}, this result indicates that melting mechanisms don't impact the melting temperature in equilibrium melting. Our melting curve is substantially higher than the one determined in diamond anvil cell experiments, agree with the shock wave measurement. [Preview Abstract] |
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F1.00155: MATERIALS SCIENCE |
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F1.00156: Ti-Si photocatalyst for producing hydrogen synthesized by shock wave Jianjun Liu, Hongling Zhang, Pengwan Chen, Xiang Gao Ti-Si binary system shows several intermetallic compounds such as TiSi$_{2}$ and Ti$_{5}$Si$_{3}$. Among them TiSi$_{2}$ and Ti$_{5}$Si$_{3}$ show the higher reaction heat and can be initiated by shock wave and will propagate and complete in the form of combustion waves. As new functional materials, the light-absorption characteristics in UV-visible region of Ti-Si compound are ideal for solar applications and have a good photocatalytic activity of splitting water into hydrogen. We have synthesized TiSi$_{2}$ and Ti$_{5}$Si$_{3}$ compound with different Ti/Si ratios by shock-induced reaction arisen from the flyer impact driven by detonation of nitromethane. It is found that TiSi$_{2}$ is formed while flyer velocity is at 3.37km/s and exhibits certain photocatalytic activity of splitting water into hydrogen compared with the unreacted Ti+Si precursor shocked at 3.07km/s. Consequently, Ti$_{5}$Si$_{3}$ synthesized at 3.37km/s has much better photocatalytic activity of splitting water into hydrogen than that of TiSi$_{2}$ synthesized by shock wave at identical condition. The experimental results suggest that shock-induced reaction of Ti and Si with different ratios might get some novel functional materials for photocatalytic or photovoltaic application. [Preview Abstract] |
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F1.00157: Microsecond current output in PbNb(Zr,Sn,Ti)O3 ceramic under shock wave compression Jiang Dongdong, Du Jinmei, Yang Jia, Gu Yan, Feng Yujun Technology of high power pulse has been the core of many scientific and engineering applications. Shock wave-driven ferroelectric power supply is smaller, lighter and at the same time more powerful than traditional technology. We reported the shock wave induced current output of PbNb(Zr,Sn,Ti)O3 ceramic. Chosen composition was Pb0.99Nb0.02[(Zr0.90Sn0.10)0.96Ti0.04]0.98O3 and near the ferroelectric and antiferroelectric phase boundary. Shock wave obtained via gas-gun projectile impact ranged from 0.24 to 2.50 GPa and depolarized ceramics in the normal mode, in which the shock propagation vector was perpendicular to the remanent polarization. Variation of electric field was by selecting a load resistor. Output currents under short-circuit and high-impedance conditions were obtained. Results suggest that PbNb(Zr,Sn,Ti)O3 is a promising material for a source of power supply and provide a basis for future pulse power design. [Preview Abstract] |
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F1.00158: Ratchet Growth Experiments on TATB and PBX 9502 Racci DeLuca, Darla Thompson, Geoff Brown, Brian Patterson, Mary Sandstrom, Stephanie Hagelberg TATB (triaminotrinitrobenzene) crystals are graphitic in structure. In compressed form, with or without binder, TATB undergoes irreversible volume changes upon thermal cycling. This ``ratchet growth'' can reduce the density by several percent. Independent studies have been conducted by us to analyze and understand ratchet growth mechanisms. Using thermo-mechanical analysis and dilatometry, strain values are measured in real time as temperature cycling protocols are varied. Initial work on PBX 9502 (95 weight{\%} TATB) has led to new studies on dry-pressed TATB cylinders, thus eliminating binder contributions to the thermal response. In another study, PBX 9502 cores were unconfined or axially-confined during the thermal cycling process. The mechanical response of thermal-cycled material was observed to be different than that of as-pressed, equivalent-density material. We have used micro x-ray computed tomography to image dry-pressed TATB specimens ($\sim $3 mm cylinders) before and after extreme thermal cycling to quantify pore size distribution changes. The results of these tests provide a more complete picture of ratchet growth in these materials and the mechanisms involved. LA-UR 11-01097. [Preview Abstract] |
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F1.00159: Electron microscopic observation in femtosecond laser-driven shock compressed silicon Masashi Tsujino, Tomokazu Sano, Kazuto Arakawa, Tomoyuki Terai, Norimasa Ozaki, Hirotato Mori, Tomoyuki Kakeshita, Ryosuke Kodama, Akio Hirose, Osami Sakata, Masayuki Okoshi, Narumi Inoue, Kojiro Kobayashi We observed microstructure in a femtosecond laser-driven shock compressed silicon using transmission electron microscope. A high-pressure phase was observed in the region where dense defects exist in diamond type structures with the dark field image using the spot obtained diffraction from the high-pressure phase theoretically. The high-pressure phase observed in these experiments is $\beta $-Sn type structure which is stable under the pressure of around 11 to 13 GPa. The phase has never remained and transforms to not diamond type structure but metastable structures after static and conventional dynamic compressions. We also confirmed that the lattice defects induced by the femtosecond laser-driven shock were denser than the statically compressed silicon using diamond anvil cell. We suggest that the dense defects play an important role in the quenching of the high-pressure phase. We will address a mechanism of the quenching of high-pressure phases of silicon using the femtosecond laser-driven shock wave. [Preview Abstract] |
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F1.00160: Characterization of shock-loaded nanocrystallite silicon powder Hiroaki Kishimura, Hitoshi Matsumoto Shock compactions of nanocrystallite silicon powder with an average particle size of 50 nm were performed using a propellant powder gun. A copper plate 30 mm in diameter was accelerated to a copper capsule with an infill of nanocrystallite silicon powder pressed to 40{\%} of the theoretical maximum density. The pressure generated in silicon powder was calculated to be below 3.6 GPa. The products of shock compression were examined by X-ray diffraction (XRD) analysis and Raman spectroscopy. The shocked samples were well consolidated, but the color of the samples changed from yellow to gray. No additional peak other than the diamond structure of silicon was observed in the XRD traces and Raman spectra. The particle size of the shocked nanocrystallite silicon was larger than that of the starting powder. Such coarsening may be enhanced by shock-induced heat. [Preview Abstract] |
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F1.00161: Localization of martensite near spall surface when shock-wave loading of stainless steel Alexander Shestakov, Alexander Pavlenko, Svetlana Malygina, Konstantin Toporistchev, Igor Svyatov, Yuriy Zouev Results of x-ray investigation of distribution of deformation martensite in samples of stainless steel 12X18H10T, which undergone spall fracture under shock-wave loading are presented in this paper. Localization of deformation martensite near the spall surface was found. An estimation of layer thickness where localization takes place was done. [Preview Abstract] |
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F1.00162: Gas Gun Studies of Interface Wear Effects Tyler Jackson, Greg Kennedy, Naresh Thadhani The characteristics of interface wear were studied by performing gas gun experiments at velocities up to 1km/s. The approach involved developing coefficients of constitutive strength models for Al 6061 and OFHC-Cu, then using those to design die geometry for interface wear gas gun experiments. Taylor rod-on-anvil impact experiments were performed to obtain coefficients of the Johnson-Cook constitutive strength model by correlating experimentally obtained deformed states of impacted samples with those predicted using ANSYS AUTODYN hydrocode. Simulations were used with validated strength models to design geometry involving acceleration of Al rods through a copper concentric cylindrical angular extrusion die. Experiments were conducted using 7.62mm and 80mm diameter gas guns. Differences in the microstructure of the interface layer and microhardness values illustrate that stress-strain conditions produced during acceleration of Al through the hollow concentric copper die, at velocities less than 800m/s, result in formation of a layer via solid state alloying due to severe plastic deformation, while higher velocities produce an interface layer consisting of melted and re-solidified aluminum. [Preview Abstract] |
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F1.00163: Attempt to measure adhesive property of particles on building materials by laser shock spallation method Manabu Satou Adhesive properties of suspended particulate matter on building materials is of interest from a view point of environmental issues. Macroscopic diffusion of the matter in urban area may have some correlation to the adhesive properties. An attempt was carried out to measure the adhesion property of particles by laser shock spallation method. The particles prepared by several conditions of dry and smear showed different behavior of removal by Nd:YAG laser irradiation that created shock wave. [Preview Abstract] |
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F1.00164: Strength and destruction of flat ampoules during shock -- wave tests Oleg Drennov Devices with nondestructive plane ampoules which permit testing specimens with volume up to 35 cm$^{3}$ under different conditions of explosive action with the intensity up to 100 GPa included are developed. Strength properties of ampoules made of different steels are evaluated under dynamic loading. These devices and ampoules are used for study of physical and chemical processes, which occur in substances under pulse effects of high strain rate, pressures and temperatures. The most promising materials are determined. Schemes are presented for flat recovery ampoule and loading devices required for providing the following loading conditions: \begin{center} 10 GPa $\le $ $\le $ 100 GPa; 0.5 $\mu $s $\le \quad \tau \quad \le $ 5 $\mu $s. \end{center} [Preview Abstract] |
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F1.00165: Quasi-isentropic compression of gaseous helium in cylindrical constructions in pressure range from 130 to 500 GPa Mikhail Zhernokletov, Vladimir Arinin, Viktor Buzin, Yulia Grigorieva, Nicholas Davydov, Viktor Khrustalev The work includes results of experiments on research of gaseous helium with initial density $\rho _{0He}$~=~0.019 g/cm$^{3}$ when compressing it in cylindrical constructions, which transform shock compression to quasi-isentropic compression. Using the techniques of preliminary static compression by pressure of 12 MPa and dynamic compression with use of HE, pressures from 130 to 460 GPa were achieved in helium at densities from 1.3 to 2.3~g/cm$^{3}$. The helium density was determined by the X-ray radiography method basing on location of boundaries of the steel shells, which compressed gas. For recording X-ray images of the shells in the experiments, we used the diagnostics system, including the DC-complex for digital X-ray radiography. The pressures were obtained basing on gasdynamic calculations. Experimental data were compared to calculations by the helium EOS, which had been developed basing on the updated model of compressed covolume. The obtained data testify to absence of anomalies due to phase transition in the investigated area of pressures and densities. [Preview Abstract] |
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F1.00166: PHYSICS AND CHEMISTRY AT HIGH PRESSURE: STATIC AND LOW RATE STUDIES |
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F1.00167: Neutrosophic Diagram and Classes of Neutrosophic Paradoxes, or To the Outer-Limits of Science Florentin Smarandache These paradoxes are called ``neutrosophic'' since they are based on indeterminacy (or neutrality, i.e. neither true nor false), which is the third component in neutrosophic logic. We generalize the Venn Diagram to a Neutrosophic Diagram, which deals with vague, inexact, ambiguous, illdefined ideas, statements, notions, entities with unclear borders. We define the neutrosophic truth table and introduce two neutrosophic operators (\textit{neuterization }and \textit{antonymization }operators) and we give many classes of neutrosophic paradoxes that may occur in sciences. [Preview Abstract] |
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F1.00168: The High-Pressure Characterization of Energetic Materials: Dihydrazinium 5, 5'-azotetrazolate dihydrate Jennifer Ciezak Jenkins The isothermal structural properties, equation of state, and vibrational dynamics of the high-nitrogen material Dihydrazinium 5, 5'-azotetrazolate dihydrate (HAT) were studied under high-pressure using synchrotron X-ray diffraction and optical Raman and Infrared microspectroscopy. At pressures near 4.5 GPa, X-ray diffraction characterization revealed an abrupt discontinuity in the compressibility, which when correlated with the mode splitting and intensity changes observed in the spectroscopic measurements, suggests the onset of a subtle isostructural phase transition. This paper will discuss the structural characteristics of the high pressure phase of HAT as well as its implications for the energetic properties of the material. [Preview Abstract] |
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F1.00169: Confocal microscopy of fluids under static pressure M.D. McCluskey, G.J. Hanna There are few reliable methods for obtaining equations of state for fluids under extreme conditions. We have used \textit{confocal microscopy} to investigate water and argon under large hydrostatic pressures. Unlike conventional optical microscopy, confocal microscopes collect data point-by-point, enabling three-dimensional image reconstruction. Using this method, we produced three-dimensional images of fluids under large hydrostatic pressures. By combining these images with Fabry-Perot interference measurements, we determined the volume and refractive index, as a function of pressure, in the same experiment. [Preview Abstract] |
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F1.00170: PARTICULATE/POROUS MATERIALS |
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F1.00171: Simulations of Shear Mixing of Bidisperse Cohesive Particles with a Large Size Range Lee Aarons The mixing of granular materials is generally a difficult task. Differently sized particles will tend to segregate, and particles less than 100 microns in diameter tend to agglomerate due to cohesive forces exceeding the weight of a particle. The primary purpose of the present study is to examine the influence of particle cohesion on the homogeneity of mixtures of cohesive particles featuring a large range of particle sizes. As a model problem, we consider discrete element method simulations of bidisperse collections of cohesive particles with a diameter ratio of 7:1 undergoing shear flow as a means of mixing. Simulations were performed with and without gravity along with different particle cohesive strengths and shear rates. Without gravity, the small particles needed to be more cohesive than some threshold to result in significant clustering, in which case the best mixing was achieved when the big particles were equally as cohesive as the small ones. With gravity, continuous shearing caused the particles to first mix and then separate again. The homogeneity just before de-mixing started was found to generally improve with decreasing cohesion. [Preview Abstract] |
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F1.00172: Collapse of a collection of nanovoids in f.c.c. and b.c.c. metals E.M. Bringa, C.J. Ruestes, J.R. Nieva, K. Olney, D. Benson Experiments that probe pressure-induced nanovoid collapse at the relevant nanoscopic length and time scales are extremely difficult or impossible with current set-ups, and continuum models might not work at the nanoscale. As a result, atomic-scale simulations can provide unique insights, possible links to models at the micro-scale, and help interpretation of experiments that average over the macroscale. We extend our previous molecular dynamics (MD) simulations of a single nanovoid collapse in both face centered cubic (fcc) and body centered cubic (bcc) metals, to the collapse of a collection of nanovoids. Pre-existing spherical nanovoids, with a radius of 3-4 nm, provide an initial porosity of 5{\%}-20{\%} for the samples studied. For fcc Au, shear loops are nucleated at void surfaces leading to significant softening, followed by Taylor-style hardening above a certain dislocation density. For bcc Ta, full dislocations are nucleated and also lead to significant softening. We examine strain rate effects, from 10$^{7}$/s to 10$^{10}$/s, in the dislocation density and dislocation-induced heating. Comparison with continuum calculations including crystal plasticity will also be presented. [Preview Abstract] |
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F1.00173: Fracture of nanoceramics with porous structure at shock wave loadings Evgeniya Skripnyak, Vladimir Skripnyak, Vladimir Skripnyak Features of deformation and damaging of porous nanoceramics and nanocomposites under shock wave loadings with amplitudes up to 10 GPa on were investigated on the meso-scale levels by a computer simulation method. The two-level model was applied to the description of the mechanical response of representative volume of structured ceramics. The fracture of oxide, boride and carbide ceramics under pulse loading is associated with the nucleation and growth of cracks on the mesolevels. Process of a fragmentation is governed by laws of shift and rotation of the formed blocks parted by cracks. Laws of formation and movement of block substructures in models of oxide and boride ceramics and ceramic nanocomposites depends on sizes, shapes of voids, and their volume distribution. The sizes of blocks surpass the average sizes of grains and have distribution. The formation of blocks and their movement under dynamic loads occurs in essentially non-stationary and non-uniform field of stress. As a result, laws of ceramics fragmentation depend on amplitudes and durations of stress pulses. Presence of voids of the micron size or clusters of nano-voids in the considered classes of ceramics causes the decrease of the Hugoniot elastic limit, and the spall strength. [Preview Abstract] |
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F1.00174: Shock Resistance of Metal-Organic Framework Cu-1,3,5-Benzenetricarboxylate with and without Ferrocene Inclusion Q. Wei, H.W. Xu, S.N. Luo A first-of-the-kind study on the dynamic response of a metal-organic framework (MOF) material to impulsive shock wave loading is reported. MOF Cu-1,3,5-benzenetricarboxylate (Cu-BTC) without and with ferrocene inclusion show anisotropic structural collapse under shock loading, likely due to the elastic anisotropy of the network structure. The shock resistance of Cu-BTC framework is enhanced drastically (by a factor of six) via including ferrocene into the pore structures. [Preview Abstract] |
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F1.00175: Shock-Precursor Waves in Granular Materials William Neal, David Chapman, William Proud Shock compaction studies of sand, and other brittle granular materials, have produced wave profiles that show an unsteady precursor-wave followed by a steady shock-wave. It is theorised that this wave is a result of the pre-compaction of the particles within the granular bed. This theory has been tested experimentally and the results are discussed. [Preview Abstract] |
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F1.00176: PHASE TRANSITIONS |
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F1.00177: Application of Electric Gun for Shock Induced Phase Transition Experiments in Iron Tao Li, Wenjun Zhu, Hong Chen, Qiang Li Electric gun can be applied in experiments for shock induced phase. The thickness of sample is comparable to the grain size of real matter. In this paper, the propagation of small distance in iron sample of about 1mm thickness is investigated to distinguish wave structure evolution of the shock induced phase transition. In the experiment, an aluminum foil is discharged into plasma to drive a 0.25mm thickness Mylar flyer through a 10mm diameter gun barrel, and the Mylar flyer is then accelerated to impact a 1mm thickness iron sample. The signal of the free-surface of the iron sample is captured by a high precision DPS interferometer. The obtained three-wave structure velocity profile in nanosecond time-scale clearly provides evidence of shock induced phase transition in the thin iron sample. [Preview Abstract] |
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F1.00178: Dielectric properties and phase transitions of TlIn(S$_{\rm{1-x}}$Se$_{\rm{x}}$)$_2$ polycrystals under pressure Oleksandr Gomonnai, Roman Rosul, Pavlo Guranich, Alexander Slivka, Mykhailo Rigan, Vasil Rubish, Alexander Gomonnai TlIn(S$_{\rm{1-x}}$Se$_{\rm{x}}$)$_2$ polycrystals belong to class of complex ferroics of different dimensionality and are interesting to be studied since they are characterized by the existence of an incommensurate phase and polycritical phenomena.. At atmospheric pressure, anomalies in the temperature interval 160--220 K are observed in the temperature dependences of dielectric constant \textit{$\varepsilon $(T)} in polycrystals TlIn(S$_{\rm{1-x}}$Se$_{\rm{x}}$)$_2$, corresponding to phase transitions into incommensurate and ferroelectric phases. In the pressure range 530 MPa $\le p <$ 660 MPa, a qualitative change of the temperature dependences of dielectric constant is observed, related to polycritical phenomena. Based on the studies of the temperature dependences of the dielectric permittivity at different hydrostatic pressures, ($p$, $T)$ phase diagrams of the TlIn(S$_{\rm{1-x}}$Se$_{\rm{x}}$)$_2$ polycrystals (0.01 $\le \quad x \quad \le $ 0.07) were built. [Preview Abstract] |
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F1.00179: Experimental Research on High Pressure Phase Transitions of Mo and Ta Ling-cang Cai, Xiu-lu Zhang, Zhong-li Liu, Zhao-yi Zeng, Jian-bo Hu Molybdenum (Mo) and Tantalum (Ta) are two of the elements forming the basis of the ultrahigh pressure scale. There are enormous discrepancies in melting curves of Mo and Ta between laser-heated diamond-anvil cell (DAC) and shock wave (SW) methods. In this work, the associated high pressure phase transitions of Mo and Ta were investigated experimentally. For Mo, several melting temperature data in the pressure range 136-390 GPa were obtained by shock wave experiments. The measured melting temperature at lowest pressure is still much higher than that of DAC experiments. Further more, by measurements of sound velocities of Ta in reverse- impact shock wave experiments, a discontinuity of logitudinal sound velocity against shock pressure at about 60 GPa was observed, which may be concluded that a solid-solid phase transition exists. [Preview Abstract] |
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F1.00180: The laser-driven isentropic compression and numerical studies of the iron alpha-epsilon transition in the context of planetology Nourou Amadou, Erik Brambrink, Tommaso Vinci, Alessandra Benuzzi-Mounaix, Michel Koenig, Thibaut De R\'esseguier, St\'ephane Mazevet, Fran\c{c}ois Guyot, Guillaume Morard, Kohei Myanishi, Norimasa Ozaki The iron alpha-epsilon transition is one of the most studied phase transition. However, in the case of isentropic compression, the influences of this transition on the high-pressure states of iron are still unknown. We will present some experimental results and their numerical simulations. During this experiment performed on the Janus laser facility (LNLL), different pressure ramp shapes were used to study the dynamic of the alpha-epsilon transition and its influences on the final thermodynamic state. These results are important for the reproducing of Earth and Super-earth core conditions (2-15 Mbar, 5000-15000 K) on laboratory where the isentropic compression is the only promise experimental scheme. [Preview Abstract] |
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F1.00181: Conductivity of manganese oxide under megabar multiple-shock pressure V.V. Avdonin, A.M. Molodets, V.E. Fortov It is known that in many substances metal-insulator transitions can not be explained by the one-electron band theory and usually associated with electron interaction. For example in compounds of transition metals the electrons of internal partially filled d- or f-shells are localized in the ionic core. Their transfer to the neighboring ions that is required for the appearance of metallic conduction is impossible due to the large loss in energy-electron interaction. Substances which are insulators for this reason (Mott insulators) are widely studied under static conditions using the diamond anvil cell basically at room temperature. This paper presents experimental data of metallization of manganese oxide under high shock pressures and temperatures. The electrical properties of MnO investigated using advanced techniques of step shock compression in little-studied region of pressures up to 100 GPa and temperatures up to 4000 K. The experimental data of electrical conductivity with their mathematical modeling can marked the high conductivity range of manganese oxide in the previously unexplored area of temperatures and pressures. This increase of electrical conductivity was interpreted as the Mott insulator-metal transition under high pressures and temperatures. This study was supported by the Presidium RAS Program ``Thermal physics and mechanics of extreme energy effects and physics of strongly compressed matter.'' [Preview Abstract] |
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F1.00182: ABSTRACT WITHDRAWN |
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F1.00183: Shock induced phase transition of different TiO$_{2}$ precursors Pengwan Chen, Xiang Gao, Jianjun Liu, Qiang Zhou To investigate the effects of phase composition and particle size on shock-induced phase transition of TiO$_{2}$, different TiO$_{2 }$precursors including MC-150 TiO$_{2}$(pure anatase,5nm), P25 TiO$_{2}$(85{\%} anatase/15{\%} rutile,15nm), T2 TiO$_{2}$(pure anatase,35nm) and T1 TiO$_{2}$(pure rutile, 24nm) were impacted by detonation-driven high velocity flyers. Powder X-ray diffraction(XRD) was used to characterize the phase composition of recovered samples. Two types of phase transition were observed, including anatase to rutile transition and anatase to high pressure phase of srilankite transition. The phase transition mechanisms and effects of shock conditions, initial phase composition and particle size were analyzed. Complete transition from anatase to srilankite can be obtained by adjusting the shock conditions. In the case of impacting pure P25 TiO$_{2}$, anatase to srilankite transition was hardly observed, which may be due to the restraint of initial phase of thermodynamically stable rutile. However, in the case of impacting a mixture of P25 TiO$_{2}$ and dicyandiamide(C$_{2}$N$_{4}$H$_{4})$, it is interesting to observe anatase to srilankite transition and the mechanisms was analyzed. [Preview Abstract] |
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F1.00184: Identifying and assessing high-pressure phase transition in iron by unique microstructure of $\alpha \to \varepsilon \to \alpha $ transitions Shu-Juan Wang, Qiu-Hong Lu, Yong-Tao Chen, Qing-Zhong Li, Yong-Bo Xu, Hai-Bo Hu, Man-Ling Sui Unique nanotwinned $\alpha $-Fe with threefold-symmetry characteristic was found in shock-compressed iron by using transmission electron microscopy (TEM). It was confirmed that the unique microstructure of $\alpha $-Fe was formed in two martensitic transformations during shock treatment, i.e. the $\alpha \to \varepsilon $ phase transition under shock loading and the $\varepsilon \to \alpha $ phase transition during unloading. The threefold-symmetry characteristic nanotwinned $\alpha $ phase is only correlated to the existence of $\varepsilon $ phase in high pressure during shock loading. Therefore, the volume percentage of the high pressure $\varepsilon $ phase under shock loadings could be assessed by measuring the $\alpha $ grains with the unique feature. A direct method to identify and assess high-pressure phase transition in iron has been developed. [Preview Abstract] |
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F1.00185: Porous silicon nitride under shock compression Vladislav Yakushev, Alexander Utkin, Andrey Zhukov The experimental results on shock loading of $\beta $-Si$_{3}$N$_{4}$ porous samples (15{\%} porosity) up to 55 GPa are presented. VISAR-recorded particle velocity profiles and measured Hugoniot show no peculiarities connected with phase transition from $\beta $-phase to high density $\gamma $-phase. However, it follows from comparison with Hugoniot for densified samples [1], the phase transition takes place. It begins at lower pressure about 25 GPa, where Hugoniot for porous samples crosses that for densified samples. The uncommon positional relationship of both Hugoniots is supposed to be connected with more powerful heating of porous material under loading which leads to reduction of pressure transition threshold. It was revealed that Lagrangian sound velocity of the samples decreases from 16 to 9 km/s in the 23-41 GPa interval. The decrease of sound velocity can be attributed to the increase in the new high density phase concentration. \\[4pt] [1] H. He, T. Sekine, T. Kobayashi, et al. //Phys. Rev. B., 62, No. 17., 11412 -- 11417 (2000). [Preview Abstract] |
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F1.00186: Measurements of sound velocities in zinc and titanium alloy by optical method Alexey Kovalev, Mikhail Zhernokletov, Alexander Mezhevov, Sergey Kirshanov, Mikhail Novikov, Lilia Kanynova Information on sound velocity, which characterizes substance behavior under conditions of shock compression followed by release, is required for formulation of substance EOS. Therefore, basing on measurement of sound velocities, it is possible to reveal phase transitions of substance along shock adiabat, including its melting. Interaction of Ti with majority of elements, on the one hand, causes significant difficulties when producing pure titanium. But, on the other hand, it gives opportunity to produce many alloys with various properties. Titanium alloy VT-20 is classified as a pseudo $\alpha$-alloy. Alongside with titanium and its alloys, zinc also is of common application as a structural material. Results are presented on measurement of sound velocities in shock-compressed zinc and alloy VT-20. The measurements were performed by rarefaction overtake method with use of indicator liquids. Basing on results of tests, boundaries of melting of zinc at its shock adiabat were revealed. The obtained experimental data were compared to available data from the other authors. [Preview Abstract] |
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F1.00187: Phase change in 080A42 plain carbon steel James De'Ath, William Proud, Gareth Appleby-Thomas, Jeremy Millett Under shock loading conditions, mild steel undergoes a solid-solid phase transition at approximately 13GPa. In this work 080A42 plain carbon steel bright round rolled bar, was machined and heat-treated to produce an annealed or a martensitic structure. These samples were shock loaded, by plate impact, and the material response recorded using \textit{in-situ} manganin stress gauges and heterodyne velocimetry. The Hugoniot stress and material characteristics both above and below the phase transition pressure have been recorded. [Preview Abstract] |
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F1.00188: SPECTROSCOPY AND OPTICAL STUDIES |
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F1.00189: Continuous wave laser irradiation of explosives David Moore, Shawn McGrane Quantitative measurements of the levels of continuous wave (CW) laser light that can be safely applied to bare explosives during contact operations were obtained at 532 nm, 785 nm, and 1550 nm wavelengths. A thermal camera was used to record the temperature of explosive pressed pellets and single crystals while they were irradiated using a measured laser power and laser spot size. No deflagration to detonation transitions were observed for the single crystals or pressed pellets in the unconfined geometry tested. Except for the photochemistry of DAAF, TATB and PBX 9502, all reactions appeared to be thermal using a 532 nm wavelength laser. The laser power thresholds for thermal damage in some of the materials at 1550 nm were significantly lower than for the 532 nm laser wavelength. No reactions were observed in any of the studied explosives using the available 300 mW laser at 785 nm wavelength. Laser damage and reaction thresholds are presented for pressed pellets of PBX9501, PBX9502, Composition B, HMX, TATB, RDX, DAAF, PETN, and TNT and single crystals of RDX, HMX, and PETN for each of the laser wavelengths. [Preview Abstract] |
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F1.00190: Quantum Chemical Studies on the Photochemistry of Nitro-Aromatic Explosives Jason Quenneville, Margo Greenfield, David S. Moore The use of temporally and spectrally shaped ultrafast laser pulses to initiate, as well as detect, high explosives is being explored at Los Alamos. High level quantum chemical calculations, presented here, provide vital support for this effort. Among the most widely-used high explosives are nitro-substituted benzene compounds such as 2,4,6-trinitrotoluene (TNT). The ground and excited electronic state potential energy surfaces of TNT and two other nitroarenes, nitrobenzene and 2,4,6-trinitroaniline (TNA) have been investigated using multi-configurational ab initio and time-dependent DFT methods. We will describe the electronic absorption spectra as well as the geometrical and energetic character of the excited state reaction coordinates and conical intersections in the three compounds. The mechanisms for radiative and non-radiative quenching of excited state population, and possibilities for control will be outlined. The photochemistries of the three compounds are compared so that general statements on the photochemistry nitro-aromatic explosives can be made. [Preview Abstract] |
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F1.00191: Microscopic states of shocked polymers Kathryn Brown, Hiroki Fujiwara, Rusty Conner, Dana Dlott We use time-resolved emission spectroscopy to characterize the behavior of dye molecules in a polymer matrix under shock pressure from laser-driven flyer plates. Using an 8 GHz displacement interferometer and a spectrograph and streak camera, we are able to simultaneously measure the impact velocity history and shock and time- and wavelength-resolved molecular emission with sub nanosecond time resolution. Since the pressure-induced emission shift has been measured independently in a diamond anvil cell, time-resolved fluorescence spectra can be used to compare the shock pressure determined by a molecular probe and the shock pressure from the impact conditions and polymer Hugoniot. Other features of the dye emission such as fluorescence depolarization and Forster energy transfer can be used to study the details of shock-induced polymer dynamics. The research described in this paper was supported by the Stewardship Sciences Academic Alliance Program from the Carnegie-DOE Alliance Center under grant number DOE CIW 4-3253-13 and by the US Army Research Office under award W911NF-10-0072. [Preview Abstract] |
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F1.00192: Interferometric analysis of cylindrically focused laser-driven shock waves in a thin liquid layer Alex Maznev, David Veysset, Gagan Saini, Steve Kooi, Thomas Pezeril, Keith Nelson Spherically and cylindrically focused shock waves are of great interest for studying fundamental aspects of behavior of materials under extreme conditions. Traditionally, converging shock waves have been studied on the spatial scale of 1 m using facilities such as implosion chambers. In this work, we apply time-resolved interferometric imaging to studying laser-driven shock waves on the microscale. Shock waves are generated in a 5 $\mu$m-thick layer of water by sub-nanosecond laser pulses focused into a ring of 100 um radius. Imaging is performed with a Mach-Zehnder interferometer by time-delayed femtosecond pulses. We obtain a series of images tracing the converging shock wave as it collapses in the focal point and then reemerges as a divergent shock wave leaving behind a cavitation bubble at the focus. Quantitative analysis of interferograms yields density and shock velocity values that match the water Hugoniot data found in the literature. The results open the prospect of spatially resolved studies of shock-compressed materials in a small-scale all-optical experiment. [Preview Abstract] |
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F1.00193: Particle velocity history of pentaerythritol tetranitrate shocked along the crystal [110] orientation by laser-accelerated miniature flyer impact Kunihiko Wakabayashi, Tomoharu Matsumura, Yoshio Nakayama, Mitsuo Koshi We performed miniature flyer impact experiments to investigate thermodynamic and optical properties of shocked single-crystal pentaerythritol tetranitrate (PETN). Thin metal plate was accelerated by irradiation of a tabletop pulsed laser and impacted on a single-crystal PETN along the [110] axis. The particle velocity history of laser-accelerated flyer was measured by using an Optically Recording Velocity Interferometer System (ORVIS). The relationship between the actual velocity and the apparent velocity measured by velocity interferometer was obtained by analyzing particle velocities just before and after the flyer impact on the PETN[110]. Particle velocity history and refractive index change of shocked PETN[110] within 10 nanoseconds just after passage of shock wave was also discussed. [Preview Abstract] |
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F1.00194: Thermal relaxation of shocked CsI with a LiF window and optical characterization of shocked LiF to 42 GPa David Boness In order to measure temperature from opaque shocked solids, such as metals of interest in condensed-matter physics and geophysics, somewhat transparent window materials have been used, especially LiF or sapphire, to carry the shock front past the interface between the two materials, while optical pyrometry measurements are made. Unfortunately, very few transparent window materials of suitable shock impedance exist. I report on several previously unpublished experiments on the transparency of shocked LiF from two-stage gas gun experiments at LANL, as well as on two experiments shocking a CsI-LiF sandwich with a known gap with fliers of 1100 Al, to a shock pressure of 42 GPa, in order to test the thermal interface relaxation predictions of Urtiew and Grover. [Preview Abstract] |
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F1.00195: Analysis of Visible Spectra and Imaging Data from Hypervelocity Impact Experiments Joseph MacFarlane, I. Golovkin, P. Woodruff, R. Nance, J. Cogar, A. Ward, W. Reinhart, T. Thornhill, J. Grun, R. Lunsford In a recent series of light-gas-gun experiments performed at Sandia National Laboratories, high-velocity aluminum projectiles impacted titanium target plates at velocities of 6 km/sec. The impact produces a hot debris cloud that expands off the rear surface of the target plate. The experiments provided data which included high-speed camera images, time-resolved emission spectra, and absolute flux levels. Data from the experiments were analyzed using hydrodynamics and radiation physics simulation codes, including the CTH shock physics code and the SPECT3D imaging and spectral analysis code. CTH is used to predict the time-dependent spatial distributions of the debris cloud material density distributions and temperatures, while SPECT3D computes simulated spectral and imaging diagnostics based on material conditions. Here, we discuss the analysis of the spectral and imaging data, including vapor temperatures determined from spectral emission lines, and overall absolute radiation flux from the debris cloud based on the calibrated imaging data. [Preview Abstract] |
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F1.00196: Shock Physics Analysis to Support Optical Signature Prediction in Hypervelocity Impacts Aaron J. Ward, Robert P. Nance, John R. Cogar, Joseph J. MacFarlane, William D. Reinhart, Thomas F. Thornhill, Jacob Grun, Robert Lunsford In a recent series of light-gas-gun experiments performed at Sandia National Laboratories, aluminum projectiles impacted titanium alloy plates at 6 km/s, with a variety of witness plates downstream. The radiative characteristics of the target debris cloud were measured using a combination of time-resolved visible emission spectroscopy and high-speed wavelength-filtered camera imagery. This paper will describe the analyses performed in support of the test series using the CTH shock-physics package from Sandia, discuss the methodology developed to port CTH results into radiation-physics codes, and provide comparisons between CTH results and experimental observations of debris-cloud shape. The combination of high-fidelity shock-physics analysis and high-fidelity spectral analysis of the shock-physics results represents a first-principles approach toward optical signature prediction in hypervelocity impacts. Details on the radiation analysis techniques and results will be presented in a companion paper. [Preview Abstract] |
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F1.00197: Thermal history sensing of post-detonation environments with thermoluminescent microparticles M. Mah, P. Armstrong, J. Lightstone, J. Talghader Thermoluminescent (TL) particles show promise as robust direct-contact thermal history sensors for explosive events. Research with microheaters has shown that TL microparticles can measure temperature excursions of hundreds of degrees; however, microheaters do not generate the severe pressure and shock stimuli present in post- detonation environments. To address this, TL particles were tested under conditions produced by the detonation of an aluminized explosive formulation. TLD-100 (LiF:Mg,Ti) powder was irradiated with 220 Gy of gamma radiation from a $^{167}$Cs source before being exposed to the free field detonation of a 20 gram charge. Particles were recovered post-detonation from two separate tests and their TL glow curves measured. At least two TL emission peaks 50 $^{\circ}$C apart are clearly distinguishable in both samples, with peak intensity ratios decreasing 33.7\% and 60.0\% from an original 8.88:1, indicative of distinct carrier traps emptying at rates depending on the trap energy. These ratios agree well with thermocouple measurements from within the post-detonation fireball. [Preview Abstract] |
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F1.00198: Underwater Laser Plasma with Reactive Fuels Joel Carney, Scott Piecuch This paper discusses the application of a nanosecond laser-shock to induce a cavitation bubble in a suspension of water and aluminum and an underwater ablation event at an aluminum target to generate the conditions under which metal fuels will oxidize with water. The energy deposited into the plasma is varied with laser energy, allowing for a laboratory-scale setting where particle reactivity can be investigated. In the case of suspended aluminum fuel particles, the bubble dynamics (expansion radius and period) are augmented by the presence of the reactive particles. Laser ablation at an aluminum surface is also accompanied by fast oxidation, augmenting the bubble formation. High-speed framing camera images along with time-resolved emission spectra are used to monitor bubble dynamics and reactivity. The critical conditions necessary to promote underwater reactivity of fuels in this laboratory setting will be used to guide future applications of reactive materials. [Preview Abstract] |
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F1.00199: POST-SHOCK TURBULENCE |
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F1.00200: Experimental and Numerical Investigations of Two Typical Richtmyer-Meshkov instabilities Jingsong Bai, Jinhong Liu, Liyong Zou, Tao Wang Two typical Richtmyer-Meshkov instabilities are investigated by experiments and simulations. One is the instability with double perturbation interface in nonuniform flows, and the other is the shock-accelerated elliptic heavy gas cylinder instability. The two experiments are conducted in the LSD's horizontal shock tube with 5 m long, 5$\times $5 cm2 square cross section and is numerical simulated by our LES code of MVFT. Good agreements have been obtained between simulations and experiment in which the visualizations of mixing interface is tracked by Schlieren photography and multiple dynamics images technology. The results illuminates that the initial nonuniform flow would have a significant effect on the RM instability, and the shape of cylinder also have a significant effect on the cylindrical RM instability. The model of shock-accelerating along the major axis has a stronger convergent effect than the one of shock-accelerating along the minor axis for elliptic gas cylinder instability. [Preview Abstract] |
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F1.00201: The Experimental Study of Dynamics of Scaled Gas-Filled Bubble Collapse in Liquid Alexander Pavlenko The article provides results of analyzing special features of the single-bubble sonoluminescence, developing the special apparatus to investigate this phenomenon on a larger-scale basis. Certain very important effects of high energy density physics, i.e. liquid compressibility, shock-wave formation under the collapse of the gas cavity in liquid, shock-wave focusing in the gas-filled cavity, occurrence of hot dense plasma in the focusing area, and high-temperature radiation yield are observed in this phenomenon. Specificity of the process is conditioned by the ``ideal'' preparation and sphericity of the gas-and-liquid contact boundary what makes the collapse process efficient due to the reduced influence of hydrodynamic instabilities. Results of experimental investigations; results of developing the facilities, description of methods used to register parameters of facilities and the system under consideration; analytical estimates how gas-filled bubbles evolve in liquid with the regard for scale effects; results of preliminary 1-D gas dynamic calculations of the gas bubble evolution are presented. The work supported by ISTC Project {\#}2116. [Preview Abstract] |
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F1.00202: Time-resolved studies of impact-initiated combustion in aluminum powder compacts Jennifer Breidenich, Sean Dixon, Brady Aydelotte, Naresh Thadhani The mechanisms of combustion reaction occurring under impact loading of aluminum powder compacts are studied using UV/Vis spectroscopy to gain time-resolved chemical information. Impact experiments performed on aluminum powder compacts reveal light emission due to reaction at velocities greater than 400m/s in air, while no reaction is observed in a vacuum (50mTorr). Light emission and reaction occurrence is also sensitive to the density of the Al powder compacts. Upon combustion, wavelengths indicative of the well-known reaction $Al+O_2 \to AlO+O$, a sharp doublet at 398nm and multiple broad peaks between 420 and 500nm, are observed. Microsecond time-resolved chemical information is gained through analysis of these wavelengths using a spectrometer coupled with an electron multiplier CCD camera. The impact initiated reaction is also monitored by high speed imaging of transient deformation profiles which are compared to those predicted using numerical simulations employing ANSYS-AUTODYN-3D computer code. The insight obtained from the combination of these analyses of impact-initiated combustion reaction in aluminum powder compacts will be presented. [Preview Abstract] |
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F1.00203: Meso-scale investigation of anaerobic chemical reactivity of Ti-Al-B powder mixtures under impact loading Manny Gonzales, Ashok Gurumurthy, Arun Gokhale, Naresh N. Thadhani Impact-initiated anaerobic chemical reactions in Ti-Al-B reactive powder mixtures under uniaxial stress conditions are investigated using a coupled experimental/computational approach. In particular, we characterize the effects of bulk composition on the threshold impact energy to initiate reaction using rod-on-anvil type tests performed on Ti-Al-B powder compacts. Statistical volume elements (SVEs) of different bulk compositions of the powder mixtures are analyzed using the continuum hydrocode CTH to quantify the effects of strain confinement and load configuration on the overall energy of the structure. These SVEs are also validated using one-point correlation functions to characterize the volume fraction and surface area of the constituents. Based on the deformation profiles from the continuum simulations, we investigate the effect of particle size distribution and clustering of Ti and B on the threshold energy required for observed reactivity. The deformation and threshold kinetic energy of the simulated system is compared with published values of the activation energy for Ti+B reactions and Al combustion in air to assess the extent of their impact-initiated reactivity. [Preview Abstract] |
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F1.00204: Characterization of Impact Initiation of Aluminum-Based Powder Compacts Michael Tucker, Sean Dixon, Naresh Thadhani Impact initiation of reactions in quasi-statically pressed powder compacts of Al-Ni, Al-Ta, and Al-W powder compacts is investigated in an effort to characterize the differences in the energy threshold as a function of materials system, volumetric distribution, and environment. The powder compacts were mounted in front of a copper projectile and impacted onto a steel anvil using a 7.62 mm gas gun at velocities up to 500 m/s. The experiments were conducted in ambient environment, as well as under a 50 millitorr vacuum. The IMACON 200 framing camera was used to observe the transient powder compact densification and deformation states, as well as a signature of reaction based on light emission. Evidence of reaction was also confirmed based on post-mortem XRD analysis of the recovered residue. The effective kinetic energy, dissipated in processes leading to reaction initiation was estimated and correlated with reactivity of the various compacts as a function of composition and environment. [Preview Abstract] |
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F1.00205: Stochastic Modeling of the Reaction Response of Reactive Intermetallic-Forming Materials Paul E. Specht, Naresh N. Thadhani, Mel R. Baer Microstructure at the meso-scale greatly affects the shock compression response of composites, due to the development of multiple wave interactions, that lead to complex loading scenarios. This microstructure-dependent response is inherently stochastic and lends itself to a probabilistic description. To understand this stochastic nature, three-dimensional simulations on a real, heterogeneous microstructure of a Ni and Al powder compact were performed in CTH, a Eulerian, finite volume hydrocode. These simulation results provide relationships between the mechanical and thermodynamic state of the composite under dynamic loading, which can be used for developing a probabilistic model for the bulk reaction response. Research funded by ONR/MURI grant No. N00014-07-1-0740. [Preview Abstract] |
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F1.00206: Mix and Instability Growth from Oblique Shock John D. Molitoris, Jan D. Batteux, Raul G. Garza, Joseph W. Tringe, P. Clark Souers We have studied the formation and evolution of shock-induced turbulent mix resulting from pre-emplaced interface features in a cylindrical geometry. In this research a solid cylindrical core of high-explosive was detonated to create an oblique shock wave that is driven through a cylindrical interface. Pre-emplaced surface features in plastic and aluminum were studied. Time sequence radiographic imaging was utilized to observe the resulting instability formation from the growth phase to onset of mix and turbulence. Different types of pre-emplaced structures at the interface resulted in a range of mix and instability conditions, with some much more effective at creating a well-mixed region. The plastic used here was porous polyethylene. Interfaces studied were between the high-explosive/aluminum, aluminum/plastic, and finally plastic/air. Radiographic image data will be compared with numerical simulations of the experiments. Partial support for this research was obtained from the Advanced Energetics Program, Defense Threat Reduction Agency. [Preview Abstract] |
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F1.00207: Riemann Solver for the Nigmatulin Model of Two-Phase Flow Kaushik Balakrishnan, John Bell, Allen Kuhl, William Howard The two-phase model of Nigmatulin (Dynamics of Multiphase Media, 1991) is revisited and a second order Godunov solver is constructed for the corresponding Riemann problem using a seven wave structure. This model differs from the well established Baer-Nunziato model in that it treats the solid phase as incompressible, and also accounts for thermal as well as elastic energies for the solid phase. Numerical results are presented for three classes of Riemann problems, demonstrating the accuracy of the method. The effect of inter-granular stress on the flow physics is investigated and it is shown that this term affects the effective stiffness of the two-phase mixture, resulting in faster wave speeds for higher stresses. In addition, the numerical methodology is tested for Shock Dispersed Fuel-type problems, and the results establish robustness of the solver for the investigation of high-speed, two-phase flow. [Preview Abstract] |
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F1.00208: Dissecting Lagrangian Velocities and Ramp Waves Daniel Orlikowski, Roger Minich Lagrangian velocities are typically the observational quantity for compression wave experiments that probe material response at high-pressure. Depending on the experimental compression methodology (high-explosive to laser), a wide range of strain rates are possible from $10^3$ to $10^8$ s$^-1$ yielding unique insight into non-linear wave propagation. We have been developing a method to understand the thermodynamic response of a material subjected to these high-pressure, compression waves. As part of that effort, we have found that the relationship between Lagrangian acceleration and the velocity offers insight into the material response and helps to dissect the velocity for subsequent analysis related to equation of state and non-elastic response mechanisms. We shall discuss this methodology and provide several examples. [Preview Abstract] |
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F1.00209: Non ideal detonation of emulsion explosives mixed with metal particles R. Mendes, J. Ribeiro, I. Plaksin, J. Campos The detonation of ammonium nitrate based compositions like emulsion explosives (EX) mixed with metal particles has been investigated experimentally. Aluminium powder with a mean particle size of 10 $\mu $m was used, and the mass concentration of aluminum on the explosive charge was ranged from 0 to 30{\%}. The values of the detonation velocity, the pressure attenuation -- P(x) -- of detonation front amplitude in a standard PMMA monitor and manganin gauges pressure-time histories are shown as a function of the explosive charge porosity and specific mass. All these parameters except the pressure-times histories have been evaluated using the multi fiber optical probe (MFOP) method which is based on the use of an optical fiber strip, with 64 independent optical fibers. The MFOP allow a quasi continuous evaluation of the detonation wave run propagation and the assessment to spatial resolved measurements of the shock wave induced in the PMMA barrier which in turns allows a detailed characterization of the detonation reaction zone structure. Results of that characterization process are presented and discussed for aluminized and non aluminized EX. Moreover, the effect of the mass concentration of the sensitizing agent (hollow glass micro-balloons) on the non monotonic detonation velocity variation, for EX, will be discussed. [Preview Abstract] |
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F1.00210: Deformation Mechanisms in Aluminum Nitride Under Shock Loading Guangli Hu, Cyril Williams, Changqiang Chen, K.T. Ramesh, J.W., McCauley Aluminum nitride (AlN) in armor applications involve not only high strains and stress rates, but also complicated stress states, such as multiaxial loading. Using a shock recovery technique, the specimens were shock loaded in a well controlled experiment and recovered for microstructural analysis. The recovered specimens were used to characterize the deformation mechanisms involved in AlN using TEM and HRTEM. The deformation mechanisms are expected to be dislocation dominated, which can be predicted through micromechanics at high pressures. Furthermore, a mechanism based constitutive model, incorporating the fracture mechanism and plasticity, is being developed to capture the dynamic response of general brittle material systems, such as AlN, alumina and silicon carbide. [Preview Abstract] |
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F1.00211: Viscoelastic Materials Study for the Mitigation of Blast-Related Brain Injury Susan Bartyczak, Willis Mock, Jr. Recent preliminary research into the causes of blast-related brain injury indicates that exposure to blast pressures, such as from IED detonation or multiple firings of a weapon, causes damage to brain tissue resulting in Traumatic Brain Injury (TBI) and Post Traumatic Stress Disorder (PTSD). Current combat helmets are not sufficient to protect the warfighter from this danger and the effects are debilitating, costly, and long-lasting. Commercially available viscoelastic materials, designed to dampen vibration caused by shock waves, might be useful as helmet liners to dampen blast waves. The objective of this research is to develop an experimental technique to test these commercially available materials when subject to blast waves and evaluate their blast mitigating behavior. A 40-mm-bore gas gun is being used as a shock tube to generate blast waves (ranging from 1 to 500 psi) in a test fixture at the gun muzzle. A fast opening valve is used to release nitrogen gas from the breech to impact instrumented targets. The targets consist of aluminum/ viscoelastic polymer/ aluminum materials. Blast attenuation is determined through the measurement of pressure and accelerometer data in front of and behind the target. The experimental technique, calibration and checkout procedures, and results will be presented. [Preview Abstract] |
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F1.00212: Features of Destruction of the Monolithic and Spaced Barriers from Anisotropic Materials at Impact Andrey Radchenko, Pavel Radchenko Creation of materials with the specified properties is an actual problem. Modern technologies of reception of materials allow to optimize strength parameters of a design for work in concrete conditions of external influences. Such optimization can be made or thanks to the imparting to a structure of a material of orderliness, or thanks to material reinforcing by strengthening elements. After such arrangement the material, as a rule, gets high rate of anisotropy. Besides optimization of properties of a material also the various approaches connected with constructive decisions are used. The spaced targets to protection of designs from high-velocity objects are especially effective. In the given work the comparative analysis of development of destructions in the monolithic and spaced targets at high-velocity interaction is carried out. A material of targets is orthotropic organoplastic with high rate of anisotropy of elastic and strength properties. Destruction, efficiency of the monolithic and spaced targets depending on orientation of properties of an anisotropic material in a range of velocities of impact from 750 to 3000m/s is investigated. [Preview Abstract] |
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