Solids

A simple equation of state for describing the behavior of solid and porous aluminum samples under shock compression and isoentropic unloading

R. K. Belkheieva

Novosibirsk State University

Abstract: A low-parametric equation of state for aluminum is constructed, in which the Grüneisen coefficient is given as a logarithmic dependence on density. The parameters of the aluminum equation of state are determined for the density range from 1.4 to 7 g/cm$^3$. The porous material is treated as a simple thermodynamically equilibrium mixture of aluminum and air. The model uses only the parameters of the equations of state and the mass fractions of the mixture constituents. The impact adiabats calculated using this model for aluminum samples with different initial porosities, re-compression curves and unloading isoentropes are found to be close to the corresponding experimental data. This indicates the applicability of the proposed approach to the construction of the equation of state of aluminum for describing the properties of this metal (in pure form and in mixtures), both in the region of repeated compression and in the region of rarefaction.

Keywords: shock adiabat, unloading isoentropy, single-continuum approximation, heterogeneous mixture, thermodynamic equilibrium, single-temperature approximation, single-velocity approximation, Grüneisen coefficient.

Received: 25.03.2023
Revised: 20.02.2025
Accepted: 11.03.2025

DOI: 10.61011/JTF.2025.07.60652.54-25

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