Bulletin of the American Physical Society
19th Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 60, Number 8
Sunday–Friday, June 14–19, 2015; Tampa, Florida
Session M1: Poster Session I (17:30 - 19:30) |
Hide Abstracts |
Chair: Marcia Cooper, Sandia National Laboratories, Jeremy Danielson, Los Alamos National Laboratory Room: Grand ABCD |
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M1.00001: DETONATION AND SHOCK INDUCED CHEMISTRY |
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M1.00002: Experimental investigation on the dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loadings Wei Huang, Wei Zhang, Dacheng Li Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of solid monolithic plates and corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick and 10mm-thick 3003 aluminum corrugated core and 5A06 face sheets are compared with the 5A06 solid monolithic plates in this paper. The dynamic deformation of plates are captured with the the 3D digital speckle correlation method (DIC). The results affirm that sandwich structures show a 30{\%} reduction in the maximum plate deflection compare with a monolithic plate of identical mass per unit area, and the peak value of deflection effectively reduced by increasing the thickness core. The failure modes of sandwich plates consists of core crushing, imprinting, stretch tearing of face sheets, bending and permanent deformation of entire structure with the increasing impulsive loads, and the failure mechanisms are analyzed with the postmortem panels and dynamic deflection history captured by cameras. [Preview Abstract] |
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M1.00003: Shock Sensitivity of a Double-Base Propellant as a Function of Size, Age, and Processing Method Harold Sandusky The shock sensitivities of a fresh and aged double-base propellant were measured with material quantities much less than that required for the conventional Large Scale Gap Test (LSGT). The Insensitive High Explosive Gap test (IHEGT) yielded the same critical initiation pressure for fresh samples using 11 g of material as the LSGT with 240 g. Results from IHEGT for the aged samples will be discussed. Challenges with different processing methods (pressing versus extrusion) owing to the limited available material and how these were overcome will also be addressed. These results demonstrate how small scale tests can mimic results in larger scale tests upon proper consideration of shock, detonation, and material science. [Preview Abstract] |
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M1.00004: Detonation Front Curvatures and Detonation Rates Lisa M. Lauderbach, K. Thomas Lorenz, Edward L. Lee, P. Clark Souers We have normalized the LLNL library of detonation front curvatures by dividing lags by the edge lag and radii by the edge radius. We then fit the normalized data to the equation L$=$AR$^{2}+$ BR$^{8}$, where L is the normalized lag and R is the normalized radius. We attribute the quadratic term to thermal processes and the 8$^{\mathrm{th}}$-power term to shock processes. We compare the {\%} of the quadratic term J at the edge with detonation rates obtained from the size effect. One class of results is made up of fine-grained, uniform explosives with large lags, where a low detonation rate leads to a high J and vice versa. This provides a rough way of estimating unknown rates if the unknown explosive is of high quality. The other, equally-large class contains rough-grained materials, often with small lags and small radii. These have curves that do not fit the equation but superfically often look quadratic. Some HMX and PETN curvatures even show a ``sombrero'' effect. Code models show that density differences of 0.03 g/cc in ram-pressed parts can cause pseudo-quadratic curves and even sombreros. Modeling is used to illustrate J at the lowest and highest possible detonation rates. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. [Preview Abstract] |
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M1.00005: A Multi-Component Model that Describes Weak Detonation in Blast Explosives D. Scott Stewart, Blaine Asay, John Bdzil, Joseph Foster, Alberto Hern\'andez, David Lambert Recently our group proposed a conceptual, multi-component model of an explosive material that admits weak (sonic) detonation. The weak detonation has the property that its propagation speed and wave structure is a function of the reaction rate of decomposition of reactants to products. The simplest version of the model assumes that a blast explosive has three components, reactants, intermediates and products. For many cases of interest this model is applicable if the first step is an endothermic reaction to intermediates followed by an exothermic reaction to products. Analysis shows that the properties of the weak detonation depend on the ratio of the first and second reaction rates. The decomposition steps, each can be endothermic or exothermic, but the overall reaction must be exothermic. We present both a theoretical and an engineering analysis of a typical explosive in this class and demonstrate by means of accompanying numerical simulations, that a three component reactive flow model that has a fast exothermic step to intermediates, followed by a slower endothermic step to final products produces weak detonation. [Preview Abstract] |
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M1.00006: ABSTRACT MOVED TO B4.00005 |
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M1.00007: ABSTRACT MOVED TO S2.00007 |
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M1.00008: ABSTRACT MOVED TO V1.00001 |
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M1.00009: ENERGETIC AND REACTIVE MATERIALS |
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M1.00010: Physicochemical and detonation properties of powerful explosive nitrates and their exploding action upon various barriers Vladimir Golubev, Thomas Klap\"otke The results on physicochemical and detonation properties for six powerful explosive nitrates such as aminotetrazolium nitrate (AT-NO$_{\mathrm{3}})$, diaminotetrazolium nitrate (DAT-NO$_{\mathrm{3}})$, diaminouronium nitrate (DAU-NO$_{\mathrm{3}})$, 1-amino-3-nitro-guanidinium nitrate (ANQ-NO$_{\mathrm{3}})$, oxalylhydrazinium nitrate (OHN) and oxalylhydrazinium dinitrate (OHDN) are presented in the paper. Physicochemical properties of these nitrates were determined with the use of methods of X-ray diffraction, nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, differential scanning calorimetry. Sensitivities to impact, friction and electrostatic discharge were determined too. All possible quantum-chemical properties of molecules and mechanisms of their decomposition were calculated using the Gaussian 09 program. Detonation properties of explosive nitrates and equations of state of detonation products in the form of Jones-Wilkins-Lee were calculated using the EXPLO5 V.6.02 program. Calculations were fulfilled for explosive materials having the maximum crystalline density and for porous and having small additions of a polymeric binder ones. Comparative calculations on determination of exploding action of examined nitrates upon barriers, plates and shells of various materials were conducted using the ANSYS Autodyn 15.0 program in plain, cylindrical and spherical statements. For comparison all similar results were obtained also for such well-known explosives as RDX and HMX. [Preview Abstract] |
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M1.00011: Shear induced controlled energy release in energetic materials Timothy Jenkins, Jennifer Ciezak-Jenkins Shearing of compressed molecular crystals has been shown to introduce both chemical reaction and phase transitions through the modifications of both the inter- and intra-molecular interactions. While most research has involved lower energy mechanochemical techniques, such as ball milling, there is the potential for significant chemistry at higher pressures and shears. Plastic and elastic deformations of crystals can potentially lead to energy release, as has been shown in previous work; however these results are not well understood. Molecular crystals have been investigated in a controlled fashion using a rotational diamond anvil cell (RDAC) with both traditional energetics and non-traditional energetics such as sucrose. The experiments provide results for validation of theory and modeling. [Preview Abstract] |
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M1.00012: The Effect of Simultaneous Shear and Pressure Loading On Nitrogen-rich Energetic Materials Farhad Forohar, Vasant Joshi, Dan Wilson, Jared Gump Current research in energetic material is focused on synthesis of high density materials. Efforts to obtain metastable high pressure and high temperature states of nitrogen using Diamond Anvil Cell (DAC) have indicated that some high density compounds may physically exist, but recovery of these materials at atmospheric pressure and temperature is still elusive. Stable poly-nitrogen compounds can be theoretically achieved by attaching them to non-nitrogen atoms. Use of combined pressure and shear is a new approach to transform material to metastable condition easier than long duration-pure pressure application of force. This new method is being applied in an attempt to synthesize and recover novel energetic materials from pre-synthesized precursors. Nitrogen rich precursors used in the present study include ammonium azide (N$_{\mathrm{4}}$H$_{\mathrm{4}})$, di-amino-tetra-azidocyclotriphosphazene (P$_{\mathrm{3}}$N$_{\mathrm{17}}$H$_{\mathrm{4}})$, and hexa-azidocyclotriphosphazene (P$_{\mathrm{3}}$N$_{\mathrm{21}})$. In order to get intramolecular interaction, co-crystallizations of mixtures were also made and subjected to pressure-shear loading. Successful decomposition of materials at low pressure has been achieved for some precursors. Additionally, the effects of pressure and shear on generating poly-nitrogen on carbon nanotubes were studied. Experimental fixture, method, results and analysis of recovered products will be presented. [Preview Abstract] |
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M1.00013: The Effect of Detonation Wave Incidence Angle on the Acceleration of Flyers by Explosives Heavily Laden with Inert Additives Jason Loiseau, William Georges, David Frost, Andrew Higgins The incidence angle of a detonation wave is often assumed to weakly influence the terminal velocity of an explosively driven flyer. For explosives heavily loaded with dense additives, this may not be true due to differences in momentum and energy transfer between detonation products, additive particles, and the flyer. For tangential incidence the particles are first accelerated against the flyer via an expansion fan, whereas they are first accelerated by the detonation wave in the normal case. In the current study we evaluate the effect of normal versus tangential incidence on the acceleration of flyers by nitromethane heavily loaded with a variety of additives. Normal detonation was initiated via an explosively driven slapper. Flyer acceleration was measured with heterodyne laser interferometry (PDV). The influence of wave angle is evaluated by comparing the terminal velocity in the two cases (i.e., normal and grazing) for the heavily loaded mixtures. The decrement in flyer velocity correlated primarily with additive volume fraction and had a weak dependence on additive density or particle size. The Gurney energy of the heterogeneous explosive was observed to increase with flyer mass, presumably due to the timescale over which impinging particles could transfer momentum. [Preview Abstract] |
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M1.00014: EQUATIONS OF STATE |
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M1.00015: Rarefaction wave propagation in transparent windows Benny Glam, Elkana Porat, Yossef Horovitz, Arnon Yossef-Hai The radial rarefaction wave velocity of polymethyl methacrylate (PMMA) and Lithium Fluoride (LiF) windows was studied by plate impact experiments and interferometery diagnostics up to pressure of 16 GPa in the PMMA and 40 GPa in the LiF. The experiments were carried out in two configurations: a) The windows were impacted directly by a metal impactor, and b) the windows were glued to Lead targets that were impacted. The VISAR measurement was done in the window interface with the target or the impactor. This information was utilized to identify the radial rarefaction arrival time to the center of different diameter windows after the shock event, and served as measurement to the radial wave velocity in the shocked material. It was found that for both windows, LiF or PMMA, the measured radial wave velocity is increasing with the pressure. Furthermore, this velocity is significantly higher than the longitudinal sound velocity calculated by the Steinberg EOS at the same pressure. In this paper we present the experimental results and a comparison to analytical calculation of the sound velocity using the Steinberg EOS. [Preview Abstract] |
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M1.00016: Cyanoacetohydrazide under pressure Gustav Borstad, Jennifer Ciezak-Jenkins The application of pressure to molecular crystals generates dramatic changes in the properties through the modification of the intermolecular interactions, the crystal structure, and the molecular bonding. Typical changes as the density increases involve the breaking of chemical bonds and the formation of new bonds. This results in the increase in the coordination number and the formation of polymers. The novel materials thus produced may possess novel properties such as high-energy density, super-hardness, high electrical and thermal conductivities and optical activity. Nevertheless, recovering these novel materials to ambient conditions has proven challenging. One approach to overcome this is seeking appropriate chemical precursors which will yield enhanced stability of the recovered material. In this poster, we present Raman data of cyanoacetohydrazide compressed using diamond anvil cell techniques. These data suggest evidence of an irreversible transformation near 20 GPa. The characteristics and stability of the recovered sample are also discussed. [Preview Abstract] |
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M1.00017: Thresholds in shock response across the elements F.L. Bourne, N.K. Bourne Compendia of shock data have been assembled across national laboratories across the world. Previous work has shown a threshold in behaviour for materials; the weak shock limit. This corresponds the stress state at which the shock is overdriven in a single front. The shock velocity-particle velocity data for elements and compounds has been systematically analysed to note discontinuities in the data. A range of materials show these features and the form of the discontinuity in each case is analysed. Some correspond to martensitic phase transformations as expected whilst others are more difficult to track down. Particular groups within the elements show characteristic forms according to groupings in the periodic table. The datasets are presented and trends are noted. [Preview Abstract] |
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M1.00018: ABSTRACT MOVED TO S5.00005 |
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M1.00019: ABSTRACT WITHDRAWN |
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M1.00020: EXPERIMENTAL DEVEOLPMENTS |
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M1.00021: Experimental investigation on underwater trajectory deviation of high-speed projectile with different nose shapes Wei Zhang, Wei Huang, Yubo Gao, Yafei Qi Laboratory-scaled oblique water entry experiments for the trajectory stability in the water column have been performed with four different nosed-projectiles at a range of velocities from 20$ m/s$ \textit{to} 250 $m/s$. The slender projectiles are designed with flat, ogival, hemi-sperical, truncated-ogival noses to make comparisons on the trajectory deviation when they are launched at vertical and oblique impact angles (0$^{^{\circ}}$ $\sim$ 25$^{^{\circ}}$). Two high-speed cameras that are positioned orthogonal to each other and normal to the column are employed to capture the entire process of projectiles' penetration. From the experimental results, the sequential images in two planes are presented to compare the trajectory deviation of different impact tests and the 3D trajectory models are extracted based on the location recorded by cameras. Considering the effect influenced by the impact velocities and noses of projectiles, it merited concluded that trajectory deviation is affected from most by impact angle, and least by impact velocities. Additionally, ogival projectiles tend to be more sensitive to oblique angle and experienced the largest attitude changing. [Preview Abstract] |
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M1.00022: Experimental investigation on ballistic stability of high-speed projectile in sand Wei Zhang, Yafei Qi, Wei Huang, Dacheng Li The investigation on ballistic stability of high-speed projectile in granular materials is important to the study of the earth penetrating weapon(EPW). Laboratory-scaled sand entry experiments for the trajectory in the sand have been performed with four different nosed projectiles at a range of velocities from 20 m/s to 250 m/s. The slender projectiles were designed into flat, ogival, hemi-sperical, truncated-ogival nose shapes to make comparisons on the trajectory when those projectiles were launched at vertical and oblique impact angles(0$^{\circ}$ $\sim$ 25$^{\circ}$) along a view window. A high-speed camera placed at the side of the window was employed to capture the entire process of projectiles' penetration. Basing on the comparison of different tests, theoretical analysis is carried out on the relationships between ballistic stability and associated conditions. It can be obtained that projectile with flat nose has the best ballistic stability, followed by truncated-ogival nose, and ogival nose is the least at the same velocity. Additionally, a semi-empirical model based on a corrected drag coefficient is established to predict the depth of penetration. [Preview Abstract] |
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M1.00023: Explosive Vessel for Dynamic Experiments at Advanced Light Sources Charles Owens, Christian Sorensen, Christopher Armstrong, Nathaniel Sanchez, Brian Jensen There has been significant effort in coupling dynamic loading platforms to advanced light sources such as the Advanced Photon Source (APS) to take advantage of X-ray diagnostics for examining material physics at extremes. Although the focus of these efforts has been on using gun systems for dynamic compression experiments, there are many experiments that require explosive loading capabilities including studies related to detonator dynamics, small angle X-ray scattering on explosives, and ejecta formation, for example. To this end, an explosive vessel and positioning stage was designed specifically for use at a synchrotron with requirements to confine up to 15 grams of explosives, couple the vessel to the X-ray beam line, and reliably position samples in the X-ray beam remotely with micrometer spatial accuracy. In this work, a description of the system will be provided along with explosive testing results for the robust, reusable positioning system. [Preview Abstract] |
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M1.00024: Tabletop Optical Diagnostics for Shock Compression of Liquids Will Bassett A novel platform for probing chemical properties in shocked liquids has recently been developed. A target cell consisting of around two hundred cuvettes roughly fifty microns deep for use with the laser-launched flyer plate apparatus developed in our group which takes advantage of our ability to perform more than a hundred launches per day. Modeling of the shock events suggests that we can access pressures between two and thirty GPa and temperatures as high as 1500 kelvin in liquid phase materials through impact driven shocks lasting tens of nanoseconds. The tabletop scale of our laser-launched flyer apparatus allows for a variety of techniques for optical diagnostics of shocked states such as fluorescence emission, infrared absorption, and Raman scattering. Preliminary results on Rhodamine 6G in glycerol shocked to 4 GPa show fluorescence red shifts of tens of nanometers. Initially, fluorescence emission of pH-indicator dyes will be used to monitor dissociation of water under shock. Future efforts will include temperature measurements during shocks using the Stokes:anti-Stokes ratios in Raman scattering and chemical compositions of reacting liquids determined through infrared absorption. [Preview Abstract] |
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M1.00025: ABSTRACT MOVED TO L2.00007 |
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M1.00026: Sub-Second Laser Heating of Thermal Impulse Sensors Hergen Eilers, Ray Gunawidjaja, Helena Diez-y-Riega, Benjamin Anderson We are reporting on thermal impulse sensors capable of measuring temperature and time for sub-second heating events. We previously tested these sensors in our laboratory for temperatures above about 700 $^{\circ}$C and for heating duration times between 2 s and 60 s. We are now evaluating these sensors for an extended temperature range and for heating times as short as 100 ms. The functionality of these sensors is similar to that of our temperature-only sensors -- rare-earth ions are used to monitor temperature-induced phase changes. However, in this case two sensor materials with different phase change kinetics are mixed. In addition, a fluorescence standard is included. The spectral changes in the sensor materials depend on temperature and heating time. By combining two sensor materials, it is possible to extract information about both of these variables. The induced spectral changes depend on the specific phase changes in the sensor materials. At lower temperatures, decomposition processes dominate these changes. As the temperature increases, nucleation and grain growth become more important. The kinetics of these processes is expected to be different for the different phases. As such, calibration requires mapping of the phase diagram followed by a kinetic analysis within each phase. [Preview Abstract] |
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M1.00027: Novel Circuits for Energizing Manganin Stress Gauges Douglas Tasker This paper describes the design, manufacture and testing of novel MOSFET pulsed constant current supplies for low impedance Manganin stress gauges. The design emphasis has been on high accuracy, low noise, simple, low cost, disposable supplies that can be used to energize multiple gauges in explosive or shock experiments. Manganin gauges used to measure stresses in detonating explosive experiments have typical resistances of 50 m$\Omega $ and are energized with pulsed currents of 50 A. Conventional pulsed current supplies for these gauges are high voltage devices with outputs as high as 500 V. Common problems with the use of high voltage supplies at explosive firing sites are: erroneous signals caused by ground loops; overdrive of oscilloscopes on gauge failure; gauge signal crosstalk; cost; and errors due to finite and changing source impedances. To correct these issues a novel MOSFET circuit was designed and will be described. It is an 18-V circuit, powered by 9-V alkaline batteries, and features an optically isolated trigger, and single-point grounding. These circuits have been successfully tested at the Los Alamos National Laboratory and selected explosive tests will be described together with their results. LA-UR-15-20613. [Preview Abstract] |
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M1.00028: Towards a final analysis of lateral gauge use across the stress ranges S.A. McDonald, N.K. Bourne, J.C.F. Millett, Z, Rosenberg The non-invasive measurement of in-material states of stress and strain within loaded targets is a paradigm that has yet to be achieved. However great advances have been made in achieving this goal over the past thirty years. Advances have come in several areas. Firstly the gauge element was redesigned from a grid configuration to a T shaped wire or foil. Secondly the flow around the gauge was investigated by several workers numerically and experimentally and shown to be stable and tracking vital changes in state faithfully. Finally a staged refinement of the analysis used to deconvolve the change in resistance back to stress has given a device now fit for use as a fiducial over the range of stresses up to the weak shock limit. This work allows examination of a series of features hitherto uncommented that have been noted on the response of the elements. One of these concerns the tracking of elastic-plastic transitions in target materials due to the rapid gauge response in the new geometry. Finally the parallel analysis of material strength using the deconvolution due to Asay has shown agreement and differences between the two techniques which are noted and reconciled here. ~ [Preview Abstract] |
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M1.00029: Temporally Resolved Emissivity and Temperature Measurements of Quartz on a Light Gas Gun Minta Akin, Ricky Chau, Jeffrey Nguyen, J. Reed Patterson, W. Pat Ambrose, Neil Holmes Emissivity has long been neglected in pyrometric measurements on shocked samples. We have built and tested~a broad spectrum apparatus and developed a new target design to dynamically measure reflectance and calculate emissivity on a two stage light gas gun. Using this system, we have measured the emission of Quartz and Fused silica near melt.~ This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. [Preview Abstract] |
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M1.00030: Optical characterisation of gold films for time-resolved reflectance thermometry measurements Jasmina Music, Thomas G. White, David J. Chapman, Daniel E. Eakins The measurement of temperature represents a long-standing challenge within the field of high-pressure science. Recently, a promising time-resolved reflectance thermometry technique employing embedded gold films has been demonstrated. As an active diagnostic, reflectance thermometry is well suited for dynamic experiments generating temperatures below 1000K, where passive diagnostics such as pyrometry become infeasible due to the transient states created. A critical component of the reflectance thermometry technique is a robust optical characterisation of the gold films, decoupling the thermal and pressure contributions. Additionally, the optical properties of gold vary with both sample preparation and thermal history. With a view towards the development of a spatially-resolved reflectance thermometry technique for temperature measurement, we report the optical characterisation of a range of commercially available or deposited thin film gold samples. Reflectance spectroscopy was performed on the gold films as a function of temperature from ambient conditions to 400K, and as a function of pressure using a diamond anvil cell. The experimental data are fitted to a simple phenomenological Drude model paving the way for the calibrated films to be used during future dynamic experiments. [Preview Abstract] |
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M1.00031: ABSTRACT MOVED TO J3.00002 |
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M1.00032: FIRST-PRINCIPLES AND MOLECULAR DYNAMICS |
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M1.00033: High Pressure Structural Phase Transition and Electronic Properties of NdX (X $=$ P, As, Sb) Compounds : A First Principles Study Sanjay Kumar Singh, Rajeshwar Singh, R.P. Singh The structural and phase transition properties of NdX (X $=$ P, As, Sb) under high pressure have been investigated using an \textit{ab-initio }full potential linear augmented plane wave plus local orbitals approach within the framework of density functional theory as implanted in the WIEN2k package. In this approach the generalized gradient approximation is chosen for the exchange-correlation functional energy optimization for calculating the total energy. At ambient conditions NdX stabilize in NaCl (B1 phase) structure. Under compression, it undergoes first-order structural transition from \textit{Fm-3m} to \textit{P4/mmm} (body centre tetragonal) phase at 30.0, 24.06 and 15.1 GPa which is found to be in good agreement with the available experimental data 30.0, 24.2 and 15.0 GPa respectively. The structural properties \textit{viz}., equilibrium lattice constants, bulk modulus and its pressure derivative and volume collapse are also calculated and compared with previous calculations and available experimental data. The local spin-density approximation along with Hubbard-U corrections and spin--orbit coupling has been used for correct prediction of electronic properties. [Preview Abstract] |
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M1.00034: Thermodynamic properties and phase transitions of $\alpha $, $\gamma $ and liquid uranium: QMD and classical MD modeling Alexey Yanilkin, Kirill Migdal, Pavel Pokatashkin, Oleg Sergeev The application of molecular dynamics allows us to take into account the influence of thermal properties on thermodynamic properties and phase transitions. In this work different uranium phases are investigated at finite temperatures by means quantum and classical molecular dynamics. In order to verify simulations the lattice constants, elastic modulus, isotherms, Gruniesen coefficient and heat expansion are calculated for $\alpha $, $\gamma $ and liquid phases. The results are in good agreement with experimental data. The stability of high temperature $\gamma $ phase is discussed. The diffusion coefficient is calculated for liquid phase at different densities and pressure. The boundaries of phase stability are estimated based on QMD results. Furthermore hugoniot calculated is in a good agreement with other calculations and experimental data up to 2TPa. In order to investigate phase transitions EAM interatomic potentials are derived by force-matching method. Different parameterizations are used for different part of phase diagram to improve the reproduction of QMD data. The coexistence and transition rates of two phases are investigated based on Z- and two phase methods. [Preview Abstract] |
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M1.00035: GEOPHYSICS AND PLANETARY SCIENCE |
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M1.00036: Impact-induced degassing from antigorite and carbonates: Implications to formation of planetary atmosphere Toshimori Sekine, Ryunosuke Tachi, Koichi Shibuya, Ryouta Mihara, Takamichi Kobayashi Primitive planetary atmosphere has been thought to consist mostly of H2O and CO2 of which components were present in the building blocks of planets. The degassing dymanics of these components during impacts processes is the key to understand the origin of planetary atmosphere. According to the Hugoniot measurements, antigorite and carbonates are stable as high as 40 GPa and 100 GPa, respectively. However, meteorites are porous and can be heated to high temperatures. If the residual temperatures for porous samples are high enough for them to degas, degassing can occur at or near ambient pressure. We have investigated the degassing of serpentine (antigorite) and carbonates (CaCO3 and MgCO3) by shock recovery experiments. Impact experiments on porous powders were carried out with a propellant gun and peak pressures were estimated as the equilibrium pressure as the container. Samples were investigated by XRD, TG/DTA, SEM, and TEM. The degassing from antigorite was small below 20 GPa, but became violent at 20-60 GPa, and completed at 60 GPa. The degassing from carbonates started in a narrow pressure range (35-38 GPa) and there was no evidence for the formation of MgO and CaO. The different results between antigorite and carbonates may suggest a constrain on the origin of planetary atmosphere. Atmospheric H2O can be present frequently but CO2 will be limited only in areas subjected to strong impacts. [Preview Abstract] |
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M1.00037: Towards an Improved Understanding of Shock Effects in Recovered Samples: Application to Shocked Clay Minerals Dylan Spaulding, Sarah Stewart, Markos Hankin, Lee Wizda Samples recovered from shock-compression experiments offer a unique opportunity to understand the response of materials to extreme conditions. Correct interpretation of such experiments requires understanding the independent roles of pressure and temperature upon both compression and release. Previous shock-recovery experiments have largely ignored the thermal history of the sample or have underestimated peak pressures due to strong impedance mismatch between the sample and its surroundings. Here, we present current efforts towards increasingly controlled shock recovery schemes for the study of devolatilization in phyllosilicate clays. Shock effects may influence how volatiles within such clays are preferentially incorporated or lost during planetary accretion as well as spectral observations and interpretations of the aqueous history of planetary surfaces. We present both equation-of-state, post-shock temperature and devolatilization data for Kaolinite and Montmorillonite (up to 21 and 23 GPa, respectively) as well as post-mortem sample analysis using a variety of methods. Performance of sample recovery designs are simulated using a 3D Eulerian hydrodynamic code (CTH) and compared to experiments in order to optimize and improve sample geometries. [Preview Abstract] |
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M1.00038: Unique local structures of Ca, Ti, Fe and Zr in natural glasses formed by meteorite impact Akira Yoshiasa, Tsubasa Tobase, Maki Okube, Ling Wang, Hiroshi Isobe, Tsutomu Mashimo The local structures of cation in tektite from six strewn fields, impact-related glass, and non-impact-related glass were studied by Ca, Ti, Fe and Zr K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). Shock compression also causes local structural changes of gest and minor elements as well as transition of host structures. How to be left a record is peculiar by each element. The XAFS measurements were performed at the beam lines BL-NW10A and BL-9C, KEK, Japan. The comparison of XANES spectra and bonding distances between crystalline reference minerals and natural glasses was done. Based on the different valence states of iron, the degrees of oxidation states were estimated. The local structures of Ca, Ti and Zr ions are useful probe for physical conditions and formation process of glasses. Tektites experienced high quenching rates and a reduced atmospheric environment when they were ejected into outer space. Other impact-related glass, which was remained close to the crater, experienced a more complicated environment. The local structural changes of cation in the impact-related glass are rich in a variety. Analysis of local structure is help to compare their formation process and distinguish them. [Preview Abstract] |
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M1.00039: Impact Basin Formation on Mars: From Borealis to the Late Heavy Bombardment Erik Davies, Sarah Stewart, Robert Lillis The Martian crust preserves the imprint of 20 large ($>$1000 km) impact basins and a global dichotomy that is hypothesized to have formed via a planetary-scale impact event. The impact basin record spans the end of the Martian dynamo magnetic field, and the youngest impact basins have the cleanest shock-demagnetization signatures. The youngest basins are also the least degraded and have more pronounced crustal thinning within the structure compared to older basins. Here, we consider the mechanics of impact basin formation under a range of crustal thickness and thermal gradients on Mars. This work will help constrain the possible impact energies and impactor sizes that produced the observed basins. Basin formation is modeled using the CTH shock physics code with a fixed central gravity field in 2D and self-gravity in 3D. Previous numerical models of a Borealis-scale impact did not include the crust or a rock rheology model, however, some important differences arise from the inclusion of strength. Heating of the mantle is significantly higher in the impacted hemisphere when strength is included. Our simulations with material strength provide new insights about the viability of the impact formation hypothesis for the global crustal dichotomy. [Preview Abstract] |
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M1.00040: GRAIN SCALE TO CONTINUUM MODELING |
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M1.00041: Nonholonomic Hamiltonian Method for Meso-macroscale Simulations of Reacting Shocks Eric Fahrenthold, Sangyup Lee The seamless integration of macroscale, mesoscale, and molecular scale models of reacting shock physics has been hindered by dramatic differences in the model formulation techniques normally used at different scales. In recent research the authors have developed the first unified discrete Hamiltonian approach to multiscale simulation of reacting shock physics. Unlike previous work, the formulation employs reacting themomechanical Hamiltonian formulations at all scales, including the continuum. Unlike previous work, the formulation employs a nonholonomic modeling approach to systematically couple the models developed at all scales. Example applications of the method show meso-macroscale shock to detonation simulations in nitromethane and RDX. [Preview Abstract] |
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M1.00042: Grain Scale Modeling - Impact of Constitutive Models Cole Yarrington, Aidan P. Thompson, Tzu-Ray Shan, Ryan Wixom There are many model considerations that are unique to the grain-scale continuum approach. Most of these considerations revolve around the treatment of continuum model parameters, now applied to the fully dense matrix of material with dispersed discrete heterogeneous features. An example of this is how the equation of state (EOS) for a grain scale material must be the fully dense EOS, as opposed to the bulk EOS measured at lower densities. This poses unique validation and parameterization challenges, as most experimental data is gathered for bulk materials. We show how different theoretical tools for smaller length scales (MD, DFT-MD) can be used to calibrate the necessary models to achieve accurate simulation results. [Preview Abstract] |
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M1.00043: HIGH ENERGY PHYSICS/WARM DENSE MATTER |
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M1.00044: Thermal conductivity measurements of CH and Be by refraction-enhanced x-ray radiography Yuan Ping, Jim King, Otto Landen, Heather Whitley, Rich London, Sebastien Hamel, Phil Sterne, Amalia Panella, Rick Freeman, Gilbert Collins Transport properties of warm dense matter are important for modeling the growth of hydrodynamic instabilities near the fuel-ablator interface in an ICF capsule, which determines the mix level in the fuel and thus is critical for successful ignition. A novel technique, time-resolved refraction-enhanced x-ray radiography, has been developed to study thermal conductivity at an interface. Experiments using OMEGA laser have been carried out for CH/Be targets isochorically heated by x-rays to measure the evolution of the density gradient at the interface due to thermal conduction. The sensitivity of this radiographic technique to discontinuities enabled observation of shock/rarefraction waves propagating away from the interface. The radiographs provide enough constraints on the temperatures, densities and scale lengths in CH and Be, respectively. Preliminary data analysis suggests that the thermal conductivities of CH and Be at near solid density and a few eV temperature are higher than predictions by the commonly used Lee-More model. Detailed analysis and comparison with various models will be presented. [Preview Abstract] |
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M1.00045: INELASTIC DEFORMATIONS, FRACTURE AND SPALL |
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M1.00046: ABSTRACT WITHDRAWN |
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M1.00047: ABSTRACT MOVED TO D4.00001 |
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M1.00048: Atomic Scale Modeling of High Strain Rate Deformation and Failure of HCP Metals Karoon Mackenchery, Garvit Agarwal, Avinash Dongare A fundamental understanding of the microstructure effects on the defect evolution at the atomic resolution and the related contribution to plasticity at the macro-scales is needed to obtain a reliable performance of metallic materials in extreme environments. Large-scale molecular dynamics simulations are carried out to characterize the dynamic evolution of defect/damage structures during the deformation and failure behavior of HCP (Mg, Ti) metallic systems (single crystal and nanocrystalline at high strain rates as well as under shock loading conditions. The evolution of various types of dislocations, twins, faults, etc. and the related deformation and failure response (nucleation and growth of voids/cracks) will be discussed. The effects of strain rates on relationships between the microstructure and the strength of these materials at high strain rates and the underlying micromechanisms related to deformation and failure will be discussed. [Preview Abstract] |
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M1.00049: Multiscale modeling of composites subjected to high speed impact Minhyung Lee, Myung S. Cha, Shu Shang, Nam H. Kim The simulation of high speed impact into composite panels is a challenging task. This is partly due to the fact macro-scale simulation requires integrating the local response at various locations, i.e. integration points. If a huge number of integration points exist for enhanced accuracy, it is often suggested to calculate the micro-scale simulation using massive parallel processing. In this paper, multiscale modeling methodology has been applied to simulate the relatively thick composite panels subjected to high speed local impact loading. Instead of massive parallel processing, we propose to use surrogate modeling to bridge micro-scale and macro-scale. Multiscale modeling of fracture phenomena of composite materials will consist of (1) micro-scale modeling of fiber-matrix structure using the unit-volume-element technique; (2) macro-scale simulation of composite panels under high strain-rate impact using material response calculated from micro-scale modeling; and (3) surrogate modeling to integrate the two scales. In order to validate the predictions, first we did the material level lab experiment such as tension test. And later we also did the field test of bullet impact into composite panels made of 4 ply and 8 ply fibers. The impact velocity ranges from 300 $\sim$ 600 m/s. [Preview Abstract] |
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M1.00050: Spall Response of Ti-Based Monolithic Bulk Metallic Glasses and their Composites Rene Diaz, Manny Gonzales, Christopher Lo, Greg Kennedy, Douglas Hofmann, Naresh Thadhani Titanium-based multicomponent bulk metallic glass matrix composites (BMGMCs) and monolithic bulk metallic glasses (BMGs) are investigated using uniaxial-strain plate-on-plate impact experiments to examine the effect of microstructure morphology on spall response under high pressure and their high strain-rate deformation. BMGMCs counteract the brittle nature of monolithic BMGs through in-situ formed crystalline dendrites which increase toughness and ductility. The Hugoniot Elastic Limit (HEL) and the spall strength of the samples was determined using VISAR from experiments performed at varying impact velocities. Post-mortem microstructural characterization was done on the recovered samples and correlated with the measured damage response. Preliminary experiments performed indicate spall strength decay with increased impact stress. The spall strength ranges for BMG and BMG-MC are 1.73 - 3.09 GPa and 3.54 - 4.32 GPa, respectively. The HEL ranges are 5.61 - 6.74 GPa for BMG and 5.59 - 7.41 GPa for BMGMC. Electron microscopy of fracture surfaces reveals the role that dendrites may play on spallation of BMG composites. The variation in spall strength and HEL of the as a function of increasing impact stress and associated microstructural changes will be presented. [Preview Abstract] |
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M1.00051: Effects of chemical composition and test conditions on the dynamic tensile response of Zr-based metallic glasses F. Wang, K.J. Laws, C.P. Trujillo, A.D. Brown, E.K. Cerreta, P.J. Hazell, M.Z. Quadir, M. Ferry, J.P. Escobedo The effects of impact velocity and temperature on the dynamic mechanical behavior of two bulk metallic glasses (BMG) with slightly different elemental compositions (Zr$_{55}$Cu$_{30}$Ni$_{5}$Al$_{30}$ and Zr$_{46}$Cu$_{38}$Ag$_{8}$Al$_{38})$ have been investigated. Bullet-shaped samples were accelerated by a gas gun to speeds in the 400 $\sim$ 600m/s range and tested at room temperature and 250 $^{\circ}$C. The specimens impacted a steel extrusion die which subjected them to high strains at high strain-rates. The extruded samples were subsequently soft recovered by using low density foams. The deformed specimens were examined by optical and electron microscopy, x-ray diffraction and hardness measurements. The characterization results aided to assess the effect of chemical composition on the microstructural evolution, i.e. phase changes or crystallization, which might influence the ductility on the nominally brittle amorphous BMGs. The most significant results from this study will be presented. [Preview Abstract] |
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M1.00052: MATERIALS STRENGTH |
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M1.00053: Experimental investigation of the lateral response of Bismuth under one-dimensional shock loading Glenn Whiteman, Jeremy Millett, Gareth Appleby-Thomas, Amer Hameed, David Wood Interest in the dynamic response of bismuth is largely derived from the existence of multiple phase transitions attainable with increasing pressure. In addition, its industrial use has grown in recent years (e.g. in solder as a replacement for lead), in part due to its relatively low toxicity. While some shock experiments have been conducted on bismuth they have largely concentrated on equation of state research. To the authors' knowledge the strength behaviour under shock is not prevalent in the literature. To this end, the shear strength response both at and behind the shock has been experimentally investigated using commercial stress gauges mounted in both longitudinal and lateral orientation with respect to the loading axis. Of particular note was the potential to observe the relatively low-pressure phase transitions in the shear strength response. [Preview Abstract] |
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M1.00054: Strain-Rate Dependence of Material Strength: Large-Scale Atomistic Simulations of Defective Cu and Ta Crystals M. Abeywardhana, A. Vasquez, J. Gaglione, T.C. Germann, R. Ravelo Large-Scale molecular dynamics (MD) simulations are used to model shock wave (SW) and quasi-isentropic compression (QIC) in defective copper and tantalum crystals. The atomic interactions were modeled employing embedded-atom method (EAM) potentials. In the QIC simulations, the MD equations of motion are modified by incorporating a collective strain rate function in the positions and velocities equations, so that the change in internal energy equals the PV work on the system. We examined the deformation mechanisms and material strength for strain rates in the 10$^9$-10$^{12}$ s$^{-1}$ range For both Cu and Ta defective crystals, we find that the strain rate dependence of the flow stress in this strain rate regime, follows a power law with an exponent close to 0.40. [Preview Abstract] |
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M1.00055: PARTICULATE, POROUS AND COMPOSITE MATERIALS |
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M1.00056: ABSTRACT MOVED TO S6.00004 |
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M1.00057: Deformation and shock consolidation of various sands under explosive loading S.A. Weckert, A.D. Resnyansky Transmission of a shock wave through various geological materials is important in military applications, for assessing the effects from a buried explosive device to an above-ground target. The composition of a real soil is complex and involves multiple constituents that undergo a number of physical and mechanical transformations during the shock loading. The present study analyzes several model soils represented by limestone sand, silica sand, and a small aggregate soil. The soils are compressed using two different steel encapsulation assemblies subject to explosive compression. These set-ups attempt to vary the level of applied load to the encapsulated soil and the length of the high-temperature effects. The assemblies are instrumented with embedded manganin gauges within the encapsulation casing for comparative analysis of the waves propagating through the soil and steel encapsulation. A comparative analysis of the recovered soil samples, including a microstructural analysis focusing on the grain breakage, soil compaction and consolidation, is correlated with a CTH numerical analysis employing a multi-phase rate sensitive material model. [Preview Abstract] |
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M1.00058: On the influence of particle morphology on the post-impact ballistic response of ceramic armour materials Amer Hameed, Gareth Appleby-Thomas, David Wood, Kevin Jaansalu Recent studies have shown evidence that the ballistic-resistance of fragmented (comminuted) ceramics is independent of the original strength of the material. In particular, experimental investigations into the ballistic behaviour of such fragmented ceramics have indicated that this response is correlated to shattered ceramic morphology. This suggests that careful control of ceramic microstructure -- and therefore failure paths -- might provide a route to optimise post-impact ballistic performance, thereby enhancing multi-hit capability. In this study, building on previous in-house work, ballistic tests were conducted using pre-formed `fragmented-ceramic' analogues based around three morphologically differing (but chemically identical) alumina feedstock materials compacted into target `pucks. In an evolution of previous work, variation of target thickness provided additional insight into an apparent morphology-based contribution to ballistic response. [Preview Abstract] |
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M1.00059: Hugoniot based equation of state for solid polyurea and polyurea aerogel foams Adam Pacheco, Richard Gustavsen, Tariq Aslam, Brian Bartram The shock response of solid polyurea and polyurea aerogel foams were studied using gas-gun driven plate impact experiments. The materials reported on here are commercially available, brand named AIRLOY X103, and supplied by Aerogel Technologies, LLC. PolyUrea Solid, with nominal density 1.13 g/cm$^3$, and two aerogel foams, with nominal densities of 0.20 and 0.35 g/cm$^3$, were studied. Most experiments were of the multi-slug type in which a sample of each density was mounted on an oxygen free high conductivity copper or 6061 aluminum baseplate. In these experiments, shock velocity was measured and other shock states calculated by the impedance matching technique. Other experiments were of the front surface impact type in which the foam sample was mounted in the projectile and impacted a lithium fluoride window. Shock states were calculated using the measured particle velocity, the projectile velocity, and the lithium fluoride Hugoniot. Peak particle velocity obtained in the foam was $>$ 4.3 km/s, and peak pressure in the solid was $>$ 29 GPa. A break in the data for the solid above particle velocities of 2.0 km/s ($\sim$ 18 GPa) indicates a probable decomposition reaction. A p-$\alpha$ model with Mie-Grueneisen form for the solid reasonably replicates the data. [Preview Abstract] |
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M1.00060: Numerical modelling of closed-cell aluminium foam under dynamic loading Paul Hazell, M.A. Kader, M.A. Islam, J.P. Escobedo, M. Saadatfar Closed-cell aluminium foams are extensively used in aerospace and automobile industries. The understanding of their behaviour under impact loading conditions is extremely important since impact problems are directly related to design of these engineering structures. This research investigates the response of a closed-cell aluminium foam (CYMAT) subjected to dynamic loading using the finite element software ABAQUS/explicit. The aim of this research is to numerically investigate the material and structural properties of closed-cell aluminium foam under impact loading conditions with interest in shock propagation and its effects on cell wall deformation. A $\mu$ -CT based 3D foam geometry is developed to simulate the local cell collapse behaviours. A number of numerical techniques are applied for modelling the crush behaviour of aluminium foam to obtain the more accurate results. The simulation results are compared with experimental data. Comparison of the results shows a good correlation between the experimental results and numerical predictions. [Preview Abstract] |
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M1.00061: Visualization of Stress Propagation in Dynamically Compacted Wetted Particle Beds Bradley Marr, David Frost The high strain rate response of granular media has received considerable attention due to increasing interest in granular penetration. It has been shown under high-rate dynamic loading that dry sand particles undergo a transition in the dominant mechanism of global deformation of the particle bed from a response governed by particle slippage to one governed by particle deformation. Introduction of a liquid phase into the particle bed alters the global deformation response of the system as the liquid is capable of supporting stresses. In the present study, we investigate the stress propagation through an array of stacked glass rods immersed in liquid, under varying drop weight-induced stress loadings. Using the photoelastic nature of the glass rods, the propagation of a stress wave through the two-phase system can be visualized. Understanding the system response at the strain rates associated with drop weight testing can provide insight when extending the loading to higher strain rates achieved with flyer plate impacts. The effects of stress magnitude, array size, and rod diameter on the stress propagation are examined. [Preview Abstract] |
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M1.00062: PHASE TRANSITIONS |
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M1.00063: Structural Changes Due to Shock Compression of Ce-Al Melt-Spun Ribbons Alex W. Bryant, Christopher Wehrenberg, Jonathan D. Poplawsky, Karren L. More, Faisal Alamgir, Bruce Remington, Naresh N. Thadhani Shock compression experiments were performed on Ce-Al melt-spun ribbons. The shock-induced changes were characterized using XRD, TEM, and APT. The experiments allow for the determination of the effects of shock compression on the microstructure of the amorphous and nanocrystalline structures inherent in melt-spun ribbons. Samples of $\sim$ 1 mm x 2 mm width and $\sim$ 40 $\mu$m thickness were prepared as multi-layered stacks with $\sim$ 6 $\mu$m thick epoxy layers and subjected to laser shock loading at the Laboratory for Laser Energetics in collaboration with Lawrence Livermore National Laboratory. The layered organization allowed for multiple shocked states to be characterized from 50J and 30J laser energies due to attenuation between each layer. Synchrotron XRD analysis performed at Brookhaven National Laboratory indicate increases in grain size for the top layers of the 30J and 50J impacts and complete attenuation of this observable effect by about the 5$^{th}$ layer. TEM and APT analyses performed on a portion of the top 5 layers of the stacks at the Center for Nanophase Materials Sciences in Oak Ridge National Laboratory indicate the presence of nanocrystalline grains (\textless ) 10nm in the as-received melt-spun ribbons, and defect structures including twinning and banded regions in the shocked ribbons. [Preview Abstract] |
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M1.00064: Shock-induced phase transition on Y$_{2}$O$_{3}$:Eu$^{3+}$ studied by photoluminescence Hiroaki Kishimura, Sho Hamada, Atsushi Aruga, Hitoshi Matsumoto A series of shock-recovery experiments on Y$_{2}$O$_{3}$:Eu$^{3+}$ powder was carried out by the impact of a flyer plate accelerated by a single-stage powder-propellant gun. 5.038-g of samples were pressed into copper capsules at 64{\%} of the theoretical maximum density (TMD) of the powder. The recovered samples were characterized by X-ray diffraction (XRD) analysis, Raman spectroscopy, and photoluminescence (PL) spectroscopy. The XRD, Raman, and PL results of samples shocked at pressures of 13 GPa indicated that a phase transition from a cubic phase (C-type) to a monoclinic phase (B-type) occurred. The recovered samples shocked at 21 and 25 GPa consisted of Y$_{2}$O$_{3}$:Eu$^{3+}$ with the C-type and the B-type. Although the sample shocked at pressures of 35 GPa was consisted of the C-type and the B-type, proportion of the B-type derived from the XRD peaks decreased and no PL peaks from the B-type were observed. For recovered samples shocked at pressures of 48 GPa and above, no signatures of the B-type were obtained. These results indicated that the shock-induced phase transition were the partial completion of the phase transition. [Preview Abstract] |
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M1.00065: SOFT MATTER |
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M1.00066: Use of Taylor Rod-on-Anvil Impact Experiments to Investigate High Strain Rate Behaviour in Polyolefins David Bucknall, Amanda Luce, Abhiram Kannan, Jennifer Breidenich, Naresh Thadhani The high strain rate deformation and mechano-lumination of various polyethylenes and polypropylene is studied using Taylor rod-on-anvil impact testing. Polypropylene and low density (LDPE), high density (HDPE), and ultra high molecular weight (UHMWPE) polyethylene samples were impacted against a hardened steel anvil at velocities ranging from 50-500 m/s. High-speed imaging, time-resolved spectroscopy, and thermal imaging are employed to track the macroscopic shape change and observe mechano-lumination and heating during impact. Additionally, electron spin resonance (ESR) and gel permeation chromatography (GPC) measurements were performed on recovered impacted samples to explain the observed deformation behavior in the various polyolefins. Time-resolved spectroscopy, coupled with ESR and GPC measurements indicate that chain scission occurs during the first few microseconds of the impact event. The observed macroscopic deformation that occurs after the observed mechano-illumination event is therefore influenced by the loss of mechanical strength associated with a drop in the molecular weight of the polymer. [Preview Abstract] |
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M1.00067: Comparison of epoxy-based encapsulating materials over temperature and strain-rate Amnah Khan, William Proud The effects of varying strain rates and temperatures on the compressive response of an epoxy resin with and without alumina filler have been investigated. The samples are studied in the range of temperatures from $-20\,^{\circ}\mathrm{C}$ to $+80\,^{\circ}\mathrm{C}$ over a range of strain rates (10$^{-4}$ s$^{-1}$ to 10$^{+3}$ s$^{-1}$). Three loading devices were used to access this range: an Instron, drop weight and a Split Hopkinson Pressure Bar. Stress-strain data was obtained, along with high-speed images. The response of the materials is compared and discussed in relation to their use as encapsulants of piezoelectric systems. [Preview Abstract] |
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M1.00068: On the suitability of Synbone{\textregistered} as a tissue simulant Gareth Appleby-Thomas, Brianna Fitzmaurice, Amer Hameed, David Wood, Mike Gibson, Jonathan Painter The applicability of various materials as human tissue analogues has been a topic of increasing interest in recent years. It allows for more cost-effective experiments to be carried out, but also avoids ethical issues that would arise from using real human tissue. Synbone{\textregistered}, a porous polyurethane material, is commonly used in ballistic experiments as a bone simulant, but until now has not been characterised in terms of its dynamic behaviour. Here, the Hugoniot equation-of-state (EOS) for Synbone{\textregistered} has been derived via a series of plate-impact experiments; highlighting the importance of the underlying material structure in terms of material collapse under high strain-rates. A series of ballistic tests were also undertaken to provide further insight into the ballistic response of Synbone{\textregistered} and its potential role as a tissue simulant. This work -- following on from previous in-house studies of other tissue analogues -- has provided useful data for future simulation of this material. In addition, comparison to dynamic data for other tissue and simulant materials has highlighted the importance of considering tissue as non-monolithic; each layer of tissue should ideally be represented by its own simulant in ballistic experiments. [Preview Abstract] |
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M1.00069: FOCUS SESSION: X-RAY FREE ELECTRON LASERS AND MATERIALS |
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M1.00070: Energy Dissipation at a Shock Front in Diamond: Simulation and Comparison with Phase Contrast Imaging Data Martha Beckwith, Andreas Schropp, Yuan Ping, Damian Swift, Gilbert Collins Understanding the behavior of carbon at high pressures and temperatures is essential for predicting the structure and evolution of giant planets, such as Uranus and Neptune. Shock compression experiments on pure carbon materials, such as diamond, can provide insight into their behavior at the extreme temperatures and pressures of the giant planets. Phase contrast imaging and hydrodynamic simulations were used to examine the propagation of a shock front in diamond. As the shock front propagates through the sample, a decrease in the shock amplitude and an increase in the shock width are observed, indicating that energy dissipative processes, such as viscosity, are apparent. In addition, fractures are observed in the diamond sample behind the shock, which could also contribute to the energy dissipation at the shock front. [Preview Abstract] |
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M1.00071: FOCUS SESSION: VELOCIMETRY DIAGNOSTICS DEVELOPMENT |
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M1.00072: Radiometric STFT Analysis of PDV recordings and detectivity limit Olivier Bozier, Gabriel Prudhomme, Patrick Mercier, Laurent Berthe Photonic Doppler Velocimetry is a plug-and-play and versatile diagnostic used in dynamic physic experiments to measure velocities. When signals are analyzed using a Short-Time Fourier Transform, multiple velocities can be distinguished: by example, the velocities of moving particle-cloud appear on spectrograms. In order to estimate the back-scattering fluxes of target, we propose an original approach ``PDV Radiometric analysis'' resulting in an expression of time-velocity spectrograms coded in power units. Experiments involving micron-sized particles raise the issue of detection limit; particle-size limit is very difficult to evaluate. From the quantification of noise sources, we derivate an estimation of the spectrogram noise leading to a detectivity limit. It may be compared to back-scattering and collected power from a particle, which is increasing with its size. At least, some results from laser-shock accelerated particles using two different PDV systems are compared: it may show the improvement of sensitivity. [Preview Abstract] |
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M1.00073: Noise and Dynamic Range in Multiplexed Photonic Doppler Velocimetry Edward Daykin, Chan Jung, Edward Miller, Michael Pena, Carlos Perez, Oliver Strand We have designed and built the Multiplexed Photonic Doppler Velocimeter (MPDV) for use on any class of shock physics experiments that requires a large number of spatial points to be measured. The MPDV uses the heterodyne method to either multiplex or up-shift data channels in the frequency domain, and also employs fiber-optic delays to multiplex additional data channels in the time domain. MPDV differs in architecture from the Photonic Doppler Velocimeter (PDV) in that the MPDV employs an Erbium Doped Fiber Amplifier (EDFA) for small signal optical pre-amplification prior to photo detection. Optical amplification allows for two aspects of MPDV operation that differ from PDV: 1) use of low power (eye-safe) lasers, and 2) ability to time multiplex with minimal degradation to the signal-to-noise ratio (SNR). However, use of EDFA optical amplification within PDV or MPDV architecture also contributes noise to the spectrogram. EDFA optical noise will impact the SNR of MPDV data, and is dependent on amplifier performance, laser power, as well as optical signal attenuation due to fiber-optic delays and components. We will review this dependence and the trade-offs that exist between SNR and multiplexing architectures. [Preview Abstract] |
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