Analysis of the response of silicon carbide subjected to shock-reshock and shock-release plate-impact experiments

Abstract
This paper presents computational results, and analyses, that investigate the dynamic response of silicon carbide to reshock and release plate-impact experiments. Recently, a series of plate-impact experiments was performed that used configurations that produced either a reshock (reloading) or release (unloading) from an initial shocked state. These experiments provide material behavior for damaged (permanently deformed) silicon carbide for which previously there has been little or no data. Computations of the experiments were performed using the recently developed JHB ceramic model. Generally, the computed results were in very good agreement with the experiments. The computed results were used to help analyze and understand the test data resulting in the following findings: 1) The release waves indicate the strength of the damaged material remains approximately constant, at about 13 GPa, up to a shock stress of 62.7 GPa, but then appears to decrease to approximately 6.5 GPa at a shock stress of 87.8 GPa. 2) The wave profiles produced from reshock are sensitive to changes in material strength and also indicate that the strength of silicon carbide remains constant when reshocked from 45.6 GPa to 62.7 GPa. 3) The shear modulus does not degrade as the material damages (as has been postulated), but rather increases slightly.