Bulletin of the American Physical Society
17th Biennial International Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 56, Number 6
Sunday–Friday, June 26–July 1 2011; Chicago, Illinois
Session S1: Inelastic Deformation, Fracture, and Spall IX |
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Chair: Thibaut De Resseguier, Futuroscope/ENSMA Room: Grand Ballroom II-III |
Thursday, June 30, 2011 9:15AM - 9:30AM |
S1.00001: Characterization of RHA and Titanium 6-4 Alloys Garry Abfalter, Nachhatter Brar Rolled Homogeneous Armor (RHA) steel and Titanium 6-4 Alloy are characterized at quasi-static and high strain rates to $\sim $1700/s and high temperatures to $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $ Tm (melting temp). Room temperature stress-strain data show that the strain rate sensitivity of titanium is twice that of RHA. Temperature softening of the two alloys is investigated by performing tests at various temperatures to $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $ Tm. Flow stress of RHA at a strain rate of $\sim $1000/s decreases from about 1500 MPa at 21$^{\circ}$C to 750 MPa at $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $ Tm. In the case of Titanium flow stress decreases from about 1450 MPa to 600 MPa at $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $ Tm. Two alloys are also characterized in the torsion mode to investigate their shear response. Shear stress -- strain data are analyzed to correlate to the tension data for both the alloys. [Preview Abstract] |
Thursday, June 30, 2011 9:30AM - 9:45AM |
S1.00002: Failure Resistance of Fiber-Reinforced Ultra-High Performance Concrete (FRUHPC) Subjected to Blast Loading Brett Ellis, Min Zhou, David McDowell As part of a hierarchy-based computational materials design program, a fully dynamic 3D mesoscale model is developed to quantify the effects of energy storage and dissipation mechanisms in Fiber-Reinforced Ultra-High Performance Concretes (FRUHPCs) subjected to blast loading. This model accounts for three constituent components: reinforcement fibers, cementitious matrix, and fiber-matrix interfaces. Microstructure instantiations encompass a range of fiber volume fraction (0-2{\%}), fiber length (10-15 mm), and interfacial bonding strength (1-100 MPa). Blast loading with scaled distances between 5 and 10 m/kg1/3 are considered. Calculations have allowed the delineation and characterization of the evolutions of kinetic energy, strain energy, work expended on interfacial damage and failure, frictional dissipation along interfaces, and bulk dissipation through granular flow as functions of microstructure, loading and constituent attributes. The relations obtained point out avenues for designing FRUHPCs with properties tailored for specific load environments and reveal trade-offs between various design scenarios. [Preview Abstract] |
Thursday, June 30, 2011 9:45AM - 10:00AM |
S1.00003: Shock compression of Cu/Nb nanolaminates and coarse-grained pure Cu and Nb W.Z. Han, N.A. Mara, A. Misra, T.C. Germann, R.G. Hoagland, S.N. Luo We investigate deformation of Cu/Nb nanolaminates (synthesized via physical vapor deposition) and coarse-grained pure Cu and Nb induced by flyer plate impact. The peak pressure is about 6 GPa and the targets are soft-recovered with proper momentum traps. For the Cu/Nb nanolaminates, shock loading is applied normal or parallel to the layer interface to reveal possible anisotropy in deformation. The recovered samples are examined with transmission electron microscopy. For the shocked Cu/Nb nanolaminates, abundant deformation twins are found in the Cu layers, and only a small amount of stacking faults, in the Nb layers. For the shocked pure Cu and Nb, dislocations are widely observed besides deformation twins (in particular in Cu), and ultra-fine microstructures are induced in some regions likely due to shear localization. The shock deformation behaviors of Cu/Nb multilayers, pure Cu and Nb are compared, and possible mechanisms, discussed. [Preview Abstract] |
Thursday, June 30, 2011 10:00AM - 10:15AM |
S1.00004: Spallation Response of Ti-6Al-4V: Rear Surface Velocimetry and X-ray Tomography Samuel A. McDonald, Matthew Cotton, Neil K. Bourne, Jeremy C.F. Millett, Philip J. Withers The investigation of the dynamic tensile or spallation response of materials is generally monitored by the measurement of reload signals during rear surface velocity signals, or post-mortem by metallography of sectioned target assemblies. This latter can only reveal features in two-dimensions, although repeated sectioning can generate a three-dimensional representation of the spalled region. However, X-ray microtomography can generate three-dimensional images without the need for sectioning. In this investigation, we combine rear surface Het-V measurements on Ti-6Al-4V with X-ray microtomography of recovered targets to determine tensile failure mechanisms during dynamic loading. [Preview Abstract] |
Thursday, June 30, 2011 10:15AM - 10:30AM |
S1.00005: Tensile strength of aluminum-epoxy resin composite structure under high strain rate conditions Damien Laporte, Fr\'ed\'eric Malaise, Michel Boustie, Eric Buzaud, Jean-Marc Chevalier Plate impact and isentropic compression experiments have been conducted to study the shock response of aluminum 6061 T6/epoxy resin composite structure below 1 GPa. Damage of epoxy resin and debonding conditions have been examined by using numerical computations. The dynamic behavior of thermoset polymer is described by a non linear viscoelastic model and a progressive damage model. The failure of aluminum/epoxy resin interfaces is represented by a stress cut-off criterion. The experimental configurations have been designed so that tensile stresses are successively applied into the epoxy resin and at aluminum/epoxy resin interfaces. The computations showed mixed cohesive and adhesive failure of the composite structure. The tensile strength of the epoxy resin depended on the stress pulse duration: 290 MPa for plate impact experiments and 370 MPa for isentropic compression tests. Failure has been clearly identified on the velocity profiles measured at free surface of the aluminium back plate. These results have major interest in the way to develop adhesion tests. [Preview Abstract] |
Thursday, June 30, 2011 10:30AM - 10:45AM |
S1.00006: Spall fracture of beryllium under shock-wave loading Viktor Skokov, Vladimir Arinin, Dmitriy Kryuchkov, Vladimir Ogorodnikov, Viktor Raevsky, Konstantin Panov, Viktor Peshkov, Olga Tyupanova The work presents the fulfilled investigations for spall fracture of beryllium samples with diameter of 65 mm, thickness 7 mm, which were made via vacuum hot pressing. Samples were loaded at normal incidence of a detonation wave of the explosive charge of the TG 5/5 composition, 7, 14 and 30~mm in thickness; in so doing intensity of a shock wave was 21-25~GPa at the output from a sample. Spall fracture was formed in the sample at sample's unloading in an air gap. A velocity profile was measured at the free boundary using VISAR laser interferometer, a spall layer thickness was measured with the help of two-frame impulse X-ray radiography, a shock wave pulse profile was measured via a manganin-based gauge in a fluoroplastic base in the course of deceleration of a spall layer and of a basic part of beryllium. Hugoniot dynamic yield strength and spall strength were measured. They amounted 0.45-0.69 GPa and 0.85 GPa respectively at a strain rate of 10E4 sE-1 in the unloading part of the incident pulse. A weak dependence between the spall layer thickness and HE layer thickness was recorded in tests. The weak dependence is not described through existing damage models and points to the need to develop more sophisticated models. [Preview Abstract] |
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