Influence of Strength and Thermo-mechanical Properties of Solid Constituents on Temperature of Two Shock Loaded Porous Materials

The temperature response of copper and silicon dioxide porous materials under impact loading is investigated experimentally and numerically. The gas gun experiments employ high speed pyrometry for measurement of the thermal emission from the shock compressed porous materials through a transparent polymer window. The numerical analysis uses a two-phase thermodynamically consistent model with consideration of strain rate sensitive flow stress. The objective of the study is to assess the contribution from the two phases constituting the porous materials to the temperature shock response. The numerical investigation includes an analysis of plastic deformation of the condensed phase, material compaction, and the inter-phase heat exchange for two porous materials with distinctively different thermal, mechanical, and strength properties of the solid constituents. Using a phenomenological approach that employs conventional equations of state for the phases and viscoelastic constitutive equations for the solid constituents, results of the modeling of the materials under shock compression correlates the measured temperature of the powders if the gaseous phase is taken into account. A detailed one-dimensional analysis evaluates possible contributions of the thermo-mechanical and kinetic properties, including compaction resistance, strength, and strain rate sensitivity to the thermal emission. It is shown that the adiabatic compression of the gaseous phase and heat exchange can make a notable contribution towards the evaluated temperature. The analysis suggests that the two-phase consideration accounting for the rate sensitive strength of the solid phase is highly desirable for an accurate assessment of the thermal shock response of porous materials under mechanical and thermal non-equilibrium.