Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session L2: Materials in Extremes VIFocus
|
Hide Abstracts |
Sponsoring Units: DCOMP DMP SHOCK Chair: Ricky Chau, Lawrence Livermore National Laboratory Room: 261 |
Wednesday, March 15, 2017 11:15AM - 11:51AM |
L2.00001: Combining In-Situ X-ray Imaging with Computational Modeling to Understand Granular Deformation during Dynamic Loading Invited Speaker: Darren Pagan With new high-speed X-ray imaging techniques, we can now probe inside samples as shocks propagate in order to quantify deformation heterogeneities and their evolution with time. These new techniques are valuable for studying dynamic loading of granular systems because deformation within the bulk of these materials exhibits significant heterogeneity due to packing variation and inter-granular interactions. Critically, these data can also be used in conjunction with high-fidelity computational models in manners not previously possible with traditionally employed diagnostics. Here we will present results from X-ray absorption imaging during dynamic loading of fine-grained synthetic olivine and quantitatively analyze the development of the compaction front and its propagation. In addition, complimentary numerical simulations of the tests will be used to elucidate the experimental results. This work was performed partially under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. [Preview Abstract] |
Wednesday, March 15, 2017 11:51AM - 12:03PM |
L2.00002: Shockwave dynamics: a comparison between stochastic and periodic porous architectures Brittany Branch, Axinte Ionite, Bradford Clements, David Montgomery, Andrew Schmalzer, Brian Patterson, Alexander Mueller, Brian Jensen, Dana Dattelbaum Polymeric foams are used extensively as structural supports and load mitigating materials in which they are subjected to compressive loading at a range of strain rates, up to the high strain rates encountered in blast and shockwave loading. To date, there have been few insights into compaction phenomena in porous structures at the mesoscale, and the influence of structure on shockwave localization. Of particular interest is when the properties of the inherent mesoscopic, periodic structure begin to emerge, versus the discrete behavior of the individual cell. Here, we illustrate, for the first time, modulation of shockwave dynamics controlled at micron-length scales in additively manufactured periodic porous structures measured using \textit{in situ}, time-resolved x-ray phase contrast imaging at the Advanced Photon Source. Further, we demonstrate how the shockwave dynamics in periodic structures differ from stochastic foams of similar density and we conclude that microstructural control in elastomer foams has a dramatic effect on shockwave dynamics and can be tailored towards a variety of applications. [Preview Abstract] |
Wednesday, March 15, 2017 12:03PM - 12:15PM |
L2.00003: The Importance of the Initial State in Understanding Shocked Porous Materials Thomas R. Mattsson, Kyle R. Cochrane, J. Matthew D. Lane, Philippe F. Weck, Tracy J. Vogler, Luke Shulenburger Modeling the response of porous materials to shock loading presents a variety of theoretical challenges, however if done well it can open a whole new area of phase space for probing the equation of state of materials. Shocked porous materials achieve significantly hotter temperatures for the same drive than fully dense ones. By combining ab initio calculations of fully dense material with a model of porosity we show the critical importance of an accurate treatment of the initial state in understanding these experiments. This approach is also directly applicable to present application of tabular equations of state to the modeling of porous material. Sandia National Laboratories is a multi-mission 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] |
Wednesday, March 15, 2017 12:15PM - 12:27PM |
L2.00004: Ensemble averaged equations for cavity growth and material pulverization Duan Zhang, Christopher Long In cases of high-speed impact or shock loading, materials go through cavity growth, spall, and pulverization, while the materials change from a continuum state to a disperse, pulverized state. This work concerns the description of the material when it changes from a continuum phase to a disperse state or vice versa. The debris cloud needs to be considered as a field containing debris pieces of various sizes and shapes, as debris fragments are often too numerous to account for individually. We use the ensemble averaging method to derive averaged equations and closure terms that are applicable to this transition of the material phases. There are explicit expressions relating the closure terms to lower length scale physics. Using these expressions, the closure terms can be calculated by direct numerical simulations, or can be modeled from the understanding of the lower length scale physics. One of the closures required is the relation between the material deformation and macroscopic velocity field. This model is not typically studied by material experiments intended for constitutive relations of the material, but it is critical for correct prediction of material deformation from cavity growth to eventual breakup. In this talk we provide two examples for these models. [Preview Abstract] |
Wednesday, March 15, 2017 12:27PM - 12:39PM |
L2.00005: Laser-induced Microparticle Impact Experiments on Soft Materials Steven Kooi, David Veysset, Alexei Maznev, Yun Jung Yang, Bradley Olsen, Keith Nelson High-velocity impact testing is used to study fundamental aspects of materials behavior under high strain rates as well as in applications ranging from armor testing to the development of novel drug delivery platforms. In this work, we study high-velocity impact of micron-size projectiles on soft viscoelastic materials including synthetic hydrogels and gelatin samples. In an all optical laser-induced projectile impact test (LIPIT), a monolayer of microparticles is placed on a transparent substrate coated with a laser absorbing polymer layer. Ablation of a laser-irradiated polymer region accelerates the microparticles which are ejected from the launching pad into free space, reaching controllable speeds up to 1.5 km/s depending on the laser pulse energy and particle characteristics. The particles are monitored while in free space and after impact on the target surface with an ultrahigh-speed multi-frame camera that can record up to 16 images with time resolution of each frame as short as 3 ns. We present images and movies capturing individual particle impact and penetration in gels, and discuss the observed dynamics in the case of high Reynolds and Weber numbers. The results can provide direct input for modeling of high-velocity impact responses and high strain rate deformation in gels and other soft materials.. [Preview Abstract] |
Wednesday, March 15, 2017 12:39PM - 12:51PM |
L2.00006: Numerical Investigation of Shock Wave Propagation in Bone-Like Tissue Matt Nelms, Arunachalam Rajendran In this investigation, the effects of shock wave propagation in bone-like biomineralized tissue was investigated. The Alligator gar (Atractosteus spatula) exoskeleton is comprised of many disparate scales that provide a biological analog for potential design of flexible protective material systems. The penetration resistant fish scale was modeled by simulating a plate impact test configuration using ABAQUS\textregistered finite element (FE) software. The gar scale is identified as a two-phase, (1) hydroxyapatite mineral and (2) collagen protein, biological composite with two distinct layers where a stiff, ceramic-like ganoine overlays a soft, highly ductile bone. The geometry and variation of elastic modulus were determined from high-resolution scanning electron microscopy and dynamic nanoindentation experimentation to develop an idealized computational model for RVE-based FE simulations. The numerical analysis shows the effects of different functional material property variations on the stress histories and energy dissipation generated by wave propagation. Given the constitutive behaviors of the two layers are distinctly different, a brittle tensile damage model was employed to describe the ganoine and Drucker-Prager plasticity was used for the nonlinear response of the bone. [Preview Abstract] |
Wednesday, March 15, 2017 12:51PM - 1:03PM |
L2.00007: Pb strength Rayleigh-Taylor drive development on the National Ignition Facility Shon Prisbrey, Hye-Sook Park, Robin Benedetti, Channing Huntington, James McNaney, Ray Smith, Chris Wehrenberg, Cynthia Panas, Athanosios Arsenlis Strength can be inferred by the amount a Rayleigh-Taylor surface deviates from classical growth when subjected to acceleration. If the acceleration is great enough, even materials highly resistant to deformation will flow. We use the National Ignition Facility (NIF) to create an acceleration profile that will cause sample metals, such as Ta or Pb, to reach multi-Mbar pressures without inducing shock melting in samples. To create such a profile we shock release a stepped density reservoir across a large gap with the stagnation of the reservoir on the far side of the gap resulting in the desired pressure drive history. Low density steps (foams) are a necessary part of this design and have been studied in the last several years on the Omega and NIF facilities. We will present progress that has been made from the \textasciitilde 5 Mbar Ta drive designs that enable strength experiments on Pb. A Pb drive design has been measured on the NIF that induces peak pressure of \textasciitilde 3.5 Mbar in the metal while avoiding shock melting during the loading process. [Preview Abstract] |
Wednesday, March 15, 2017 1:03PM - 1:15PM |
L2.00008: Using Bragg Coherent Diffraction Imaging to See Strain in a Tensile Loaded Copper Film Timothy S. O'Leary, Saryu J. Fensin, Reeju Pokharel, Matthew J. Cherukara, Jorg Maser, Ross J. Harder, Richard L. Sandberg Coherent Diffraction Imaging (CDI) is a novel imaging technique using coherent light sources and iterative phase retrieval (IPR) algorithms instead of lenses to form high resolution images. Bragg coherent diffraction imaging (BCDI) is a variation of CDI that measures coherent diffraction near a Bragg peak of a crystalline sample. Since the Bragg peak contains information about lattice strain, the IPR retrieves nanometer scale images of crystalline strain. We present three dimensional BCDI reconstructions of the strain in a single grain in polycrystalline copper thin films under tensile loading measured at sector 34 of the Advanced Photon Source. [Preview Abstract] |
Wednesday, March 15, 2017 1:15PM - 1:27PM |
L2.00009: Experiments, constitutive modeling and FE simulations of the impact behavior of Molybdenum Geremy Kleiser, Benoit Revil-Baudard For polycrystalline high-purity molybdenum the feasibility of a Taylor test is questionable because the very large tensile stresses generated at impact would result in disintegration of the specimen. We report an experimental investigation and new model to account simultaneously for the experimentally observed anisotropy, tension-compression asymmetry and strain-rate sensitivity of this material. To ensure high-fidelity predictions, a fully-implicit algorithm was used for implementing the new model in the FE code ABAQUS. Based on model predictions, the impact velocity range was established for which specimens may be recovered. Taylor impact tests in this range (140-165 m/s) were successfully conducted for different specimen taken along the rolling direction (RD), the transverse direction and 45$^{\mathrm{o}}$ to the RD. Comparison between the measured profiles of impact specimens and FE model predictions show excellent agreement. Furthermore, simulations were performed to gain understanding of the dynamic event: time evolution of the pressure, the extent of plastic deformation, distribution of plastic strain rates, and transition to quasi-stable deformation occurs. [Preview Abstract] |
Wednesday, March 15, 2017 1:27PM - 1:39PM |
L2.00010: In-situ measurement of temperature during rapid thermite deflagrations John Densmore, Kyle Sullivan Thermites are composite materials that consist of a fuel (metal) and oxidizer (metal oxide), that upon reaction can release a large amount of energy (20.8 kJ/cc for Al:CuO). The time scale for a thermite to release energy (ms) is much longer than a typical detonation (us). In-situ temperature and/or thermal flux measurements can provide fundamental insight into the reaction mechanisms. This information can inform the design and optimization of energy transport during a deflagration, to optimize the energy release rate. To measure the temperature we use a burn tube apparatus and various pyrometry techniques to measure the spatial temperature field as a reaction proceeds towards completion. We show that system properties can be adjusted to achieve custom thermal properties. [Preview Abstract] |
Wednesday, March 15, 2017 1:39PM - 1:51PM |
L2.00011: Application of the thermodynamic-based strain gradient plasticity theory in high velocity impact problems George Voyiadjis, Yooseob Song In this work, a thermodynamic-based framework of the higher-order strain gradient plasticity is presented to investigate the thermo-mechanical material response of the metallic volumes at extreme conditions such as high velocity impact related problems. The need of the plastic strain gradients and their corresponding rates is discussed along with the mechanism associated with geometrically necessary dislocations. One of the major issues in the strain gradient plasticity is the determination of the intrinsic material length scales that scale with the gradient of the plastic strain. Explicit and implicit microstructural length scales, which preserve the well-posed nature of the differential equations, are introduced through the use of the viscosity and gradient localization limiters. Numerical simulations of the dynamic deformation response of tantalum hat-shaped specimens, subjected to compressive loading at the ambient initial temperatures and three different strain rates, are carried out and the comparisons of the numerical results to experimental measurements are also made. Another numerical application of a blunt projectile impacting a target is examined and the direct comparison between numerical and experimental results is presented. [Preview Abstract] |
Wednesday, March 15, 2017 1:51PM - 2:03PM |
L2.00012: Shock-induced mechanochemistry in heterogeneous reactive powder mixtures Manny Gonzales, Ashok Gurumurthy, Gregory Kennedy, Christopher Neel, Arun Gokhale, Naresh Thadhani The bulk response of compacted powder mixtures subjected to high-strain-rate loading conditions in various configurations is manifested from behavior at the meso-scale. Simulations at the meso-scale can provide an additional confirmation of the possible origins of the observed response. This work investigates the bulk dynamic response of Ti$+$B$+$Al reactive powder mixtures under two extreme loading configurations -- uniaxial stress and strain loading -- leveraging highly-resolved in-situ measurements and meso-scale simulations. Modified rod-on-anvil impact tests on a reactive pellet demonstrate an optimized stoichiometry promoting reaction in Ti$+$B$+$Al. Encapsulated powders subjected to shock compression via flyer plate tests provide possible evidence of a shock-induced reaction at high pressures. Meso-scale simulations of the direct experimental configurations employing highly-resolved microstructural features of the Ti$+$B compacted mixture show complex inhomogeneous deformation responses and reveal the importance of meso-scale features such as particle size and morphology and their effects on the measured response. [Preview Abstract] |
Wednesday, March 15, 2017 2:03PM - 2:15PM |
L2.00013: In-Situ Imaging of Particles during Rapid Thermite Deflagrations Michael Grapes, Kyle Sullivan, Robert Reeves, John Densmore, Trevor Willey, Tony Van Buuren, Kamel Fezaa The dynamic behavior of rapidly deflagrating thermites is a highly complex process involving rapid decomposition, melting, and outgassing of intermediate and/or product gases. Few experimental techniques are capable of probing these phenomena in situ due to the small length and time scales associated with the reaction. Here we use a recently developed extended burn tube test, where we initiate a small pile of thermite on the closed end of a clear acrylic tube. The length of the tube is sufficient to fully contain the reaction as it proceeds and flows entrained particles down the tube. This experiment was brought to the Advanced Photon Source, and the particle formation was X-ray imaged at various positions down the tube. Several formulations, as well as formulation parameters were varied to investigate the size and morphology of the particles, as well as to look for dynamic behavior attributed to the reaction. In all cases, we see evidence of particle coalescence and condensed-phase interfacial reactions. The results improve our understanding of the procession of reactants to products in these systems. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700