FREE SURFACE VELOCIMETRY CORRECTIONS FOR LOW PRESSURE SHOCKS

We consider how to interpret measured free surface velocities to estimate what a relatively weak shock (with an elastic-plastic two-wave structure, ∼5-30 GPa) would have looked like in an infinite sample. Hysteresis and nonlinear wave interactions introduce effects (inexact velocity doubling and the delay, partial reflection, and reverberation of waves) whose magnitudes can be estimated with simple models. We argue, and demonstrate in a simulated test case, that these estimates can eliminate most of the systematic error introduced by the free surface during loading.