Finite deformations, Onsager irreversible thermodynamics, and stress analysis of shock waves

Experimental results from a spherical source of chemical explosive in PMMA provided shock velocity, particle velocity, and stress measurements. The experimental results are used to evaluate Onsager relationships for dislocation dependent, nonequilibrium thermodynamic processes during shock wave propagation. Because shock energy is dissipated by the nonequilibrium processes, the shock wave approaches a steady wave far from the explosive source. The shapes of the measured steady wave profiles were approximately triangular for both the particle velocity and the stress histories immediately behind the shock front. Using this information, an approximate elastic analysis is performed for a triangular shock wave profile propagating from a point source. This analysis provided a model to discriminate between different diagonal components of the stress tensor that result from a spherically symmetrical shock wave. 16 refs., 4 figs.