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Using temporal pulse shaping, laser ablation can generate shocks or ramp loading in samples. Shock data can often be analyzed using analytic calculations, but integrated calculations are required in the case of ramps. When phase transitions occur, surface velocity histories may become much more complicated, requiring accurate hydrocode simulations for interpretation. The shock may be split by phase transitions and the slope of the ramp interacts with phase transition kinetics. The analysis of these experiments requires a good knowledge of phase transition thermodynamics i.e. an accurate multiphase equation of state (EOS). Recently, laser experiments have been performed on samples exhibiting phase transitions, complemented by a general model of multiphase EOS developed at CEA. The aim of the present study was to compare equilibrium multiphase EOS with qualitative and quantitative features of the experimental data. Multiphase EOS were constructed for Ti and Zr using static data. Good agreement was found between most experiments and calculations, demonstrating the accuracy of the multiphase EOS. In some cases, the experimental data show obvious kinetic effects. [ABSTRACT FROM AUTHOR]

One century ago, in 1909, finished one of the most creative decade for the progress of shock wave and detonation understanding. In 1899, Chapman provided the basis of what is called now the Chapman-Jouguet theory. During the following years, several authors (Jouguet, Hadamard, Crussard, Duhem, Dixon and the Hungarian Zemplen...) yielded important contributions to the understanding of shock wave and detonation propagation: sonicity properties, possibility of the rarefaction shock, real waves with finite thickness, real geometries and real materials, thermodynamic properties, etc... These years finished in 1909 with Duhem’s paper which gathered some properties concerning real materials. [ABSTRACT FROM AUTHOR]

Our purpose is to provide the explanation of the successive waves which can occur in the general case when a wave propagates through a material with a non-convex equation of state. We show that decrease of the sound speed introduces isentropic compression waves (ICW) inside shock waves (SW) and rarefaction shocks (RS) inside isentropic release (IR) fans. After basic phenomena explanations, we illustrate them on the example of a virtual material which gathers all these cases. Hydrocode calculations based on this material show the difficulties of high-order numerical schemes to reproduce the physical features. [ABSTRACT FROM AUTHOR]

We propose an algorithm to build complete equation of state EOS including several solid/solid or solid/liquid phase transitions. Each phase has its own EOS and independent parameters. The phase diagram is deduced from the thermodynamic equilibrium assumption. Until now, such an approach was used in simple cases and limited to 2 or 3 phases. We have applied it in the general case to bismuth for which up to 13 phases have been identified. This study shows the great influence of binary mixtures and triple points properties in released isentropes after shock waves. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

When a shock wave crosses a solid material and subjects it to solid-solid or solid-liquid phase transition, related phenomena occur: shock splitting, and the corresponding released shock wave after reflection. Modelling of these phenomena raises physical and numerical issues. After shock loading, such materials can reach different kinds of states: single-phase states, binary-phase states, and triple points. The thermodynamic path can be studied and easily understood in the (V,E) or (V,S) planes. In the case of 3 phase tin (β,γ, and liquid) submitted to shock waves, seven states can occur: β,γ, liquid, β-γ, β-liquid, γ-liquid, and β-γ-liquid. After studying the thermodynamic properties with a complete 3-phase Equation of State, we show the existence of these seven states with a hydrodynamic simulation. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]