A few-parameter equation of state of the condensed matter and its application to the impact problems

Khristianovich Institute of Theoretical and Applied Mechanics, Russian Academy of Science, 4/1 Institutskaya Str., 630090 Novosibirsk, Russia

^a e-mail: kraus@itam.nsc.ru

Abstract

A simple caloric model of the equation of state is proposed to describe thermodynamic properties of solid materials with the phase transitions being ignored and with the minimum possible number of parameters as the initial data. Thermal oscillations of the crystal lattice are described by the Debye approximation. The values of the parameters on the zero isotherm are calculated analytically from the generalized form of the Gruneisen function. Thermodynamic characteristics are calculated in wide ranges of densities and pressures. Extensive comparisons of theoretical results with experimental data available for high energy densities are performed for the materials considered. Two-dimensional problems of a high-velocity impact of a reactor of a nuclear powerplant with the Earth’s surface propulsion system are solved on the basis of Willkins’ method with allowance for the equation of state being derived.