Bulletin of the American Physical Society
18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT)
Volume 58, Number 7
Sunday–Friday, July 7–12, 2013; Seattle, Washington
Session T6: ME.3 Inelastic Deformation, Fracture, and Spall XIII |
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Chair: Zbig Dreger, Washington State University Room: Cascade II |
Thursday, July 11, 2013 9:15AM - 9:30AM |
T6.00001: Influence of Grain Boundary Properties on Spall Strength Saryu Fensin, Steve Valone, Ellen Cerreta, George Gray There are many factors thought to affect the spall strength of a grain boundary, including: grain boundary structure, energy, and excess volume, in addition to its interactions with dislocations. In this work, we explore the affect of average and local properties on the spall strength of a grain boundary. The average properties explored in this work include grain boundary energy and excess volume while local properties include plastic work at grain boundary. Flyer plate simulations were carried out for five boundary types with different structures, energies and excess volumes. These boundaries were chosen as model systems to represent various boundaries observed in ``real'' materials. Simulations indicate that there is no direct correlation between the spall strength of a boundary and either its energy and excess volume. This result suggests that average properties of grain boundaries alone are not sufficient indicators of the spall strength of a boundary and perhaps local boundary properties need to be taken into account to predict boundary spall strength. In fact, better correlation was found between the ability of a boundary to undergo plastic deformation and spall strength. [Preview Abstract] |
Thursday, July 11, 2013 9:30AM - 9:45AM |
T6.00002: On the dynamic tensile strength of zirconium Gareth Appleby-Thomas, Amer Hameed, Rade Vignjevic, Clive Siviour, Paul Hazell, Jonathan Painter Dynamic tensile failure (spall) initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to spall of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an on-going in-house body of work investigating this complex class of materials. In particular, in this paper the effects of impact stress, pulse duration and texture on spall have been interrogated using velocimetry techniques. [Preview Abstract] |
Thursday, July 11, 2013 9:45AM - 10:00AM |
T6.00003: Ballistic properties of debris produced by laser shock-induced micro-spallation of tin samples Didier Loison, Thibaut de Resseguier, Andre Dragon Dynamic fragmentation in the liquid state after melting under shock compression or upon release leads to the ejection of a cloud of droplets. This phenomenon, called micro-spallation, remains essentially unexplored in most metals. We present laser shock experiments performed on tin, to pressures ranging from about 60 to 220 GPa. Experimental diagnostics include skew Photonic Doppler Velocimetry (PDV) measurements of the droplets velocities, transverse observations of the expanding cloud of droplets, and soft recovery of ejecta within a low density gel. Optical microscopy of the gel reveals the presence of droplets which confirm shock-induced melting prior to fragmentation. To quantify size distribution of the debris, 3D X-ray micro-tomography has been performed at the ESRF synchrotron facility in France (similar to US Advanced Photon Source), where sub-micrometer resolution could be achieved. In this paper, the resulting velocity and size distributions are presented and compared with theoretical predictions based on a one-dimensional description accounting for laser shock loading, wave propagation, phase transformations, and fragmentation. Discrepancies between measured and calculated distributions are discussed. Finally, combining size and velocity data provides estimates of the ballistic properties of debris and their kinetic energy, which are key issues for anticipating the damage produced by their impacts on nearby equipments. [Preview Abstract] |
Thursday, July 11, 2013 10:00AM - 10:15AM |
T6.00004: Study on metal ejection under laser shock loading Xin Jianting, Gu Yuqiu Dynamic response of metal to shock loading plays an important role in the fields of civil engineering, aeronautics etc. The loading method of intense laser driven shock wave has many advantages to study the ejection process. The present work is devoted to laser-shock experiments in metal ejection, and get access to fragments recovery and post-test evaluation of the fragment-size distribution. The experiments were carried out on the SGIII laser facility, the samples are tin foil of 106$\mu $m and 260 $\mu $m. Two high power pulsed laser beams of 0.532$\mu $m wavelength are focused onto the target, the laser beams were homogenized by cpp, and the irradiated spot is quasi circular with 2mm diameter. The dynamic fragmentation were recovered by CH foam with 200mg/cm$_{3}$ density. One dimensional simulations were performed with HYADES code, and the pressures near the free surface of the targets driven by laser in experiments are 13Gpa, 27Gpa, 42Gpa and 50Gpa respectively. We observed the fragments in the CH foam tube by X-ray radiographs and CT image reconstruction. The total number and characteristic size of fragments have been detected.. [Preview Abstract] |
Thursday, July 11, 2013 10:15AM - 10:30AM |
T6.00005: Experimental and Numerical Study of Water-Filled Vessel Impacted by Flat Projectiles Wei Zhang, Peng Ren, Wei Huang, Yubo Gao 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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