Chapter Four - Dynamic experimental study of equation of state of solids under high pressures

Abstract

The dynamic experimental study of the equation of state for solids under high pressures is based on the shock wave theory. It is thus necessary to introduce the basic theory of shock waves first, including the generation of shock wave; the conservation conditions of mass, momentum, and energy across the shock wave front (the so-called shock jump conditions or the Rankine–Hugoniot relations), which together with the internal energy-type state equation provide the relations between any two of the five unknown quantities, called shock adiabatic relationships (or shock adiabatic curves), such as the P–V curve, P–u curve, and D–u curve. Then the incident, reflection, and transmission as well as the interactions of shock waves are discussed. On the other side, the experimental device producing different high pressures (particularly chemical explosion high-pressure technologies and gas-gun high-pressure technologies), and the corresponding dynamic diagnose techniques are discussed, so that the shock adiabatic curves can be determined, particularly the P–V curve, the P-u curve, and the D-u curve. On the basis of the above, the objective is to determine the equation of state for solids under high pressures by using the measured shock adiabatic curves. Finally, the shock phase transition and its effect on the shock adiabatic curve are briefly discussed.