Shock compression science: Dynamic material properties and computation

Constitutive models used in computational prediction of high-rate deformation related to SBSS are determined by validation experiments that can be interpreted with some degree of uniqueness and without ambiguity. Here we include not only material strength and fracture, but also equation-of-state information, and, in the case of reactive solids, initiation concepts related to material strength and fracture. By equation of state we mean material information derived from equilibrium thermodynamics. For fluids this is normally the p, V, E, T information necessary for high-pressure shock-wave applications. For elastic solids it can also be second- and third-order adiabatic elastic moduli for crystals of arbitrary symmetry. Material strength and fracture are generally related to the defect state of the material, and are thus distinct from equilibrium thermodynamics. Likewise, initiation of solid explosives is related to hot spots arising from defects such as porosity and cracking. Finally, by the term {open_quotes}validation{close_quotes} we mean the repeated comparison of a computational model with a set of interpretable experiments, each exercising a particular aspect of the model under well-controlled loading conditions. To be explicitly clear on the thrust of this section, emphasis is on the experimentation necessary to define and elucidate models. Here the role of computation is in the analysis of experiments. Of course, once the validity of a model is established with some confidence, large-scale computation can be used as a predictive tool