Pressure-shear plate impact experiment on soda-lime glass at a pressure of 30 GPa and strain rate of 4·10^7 s^(-1)

Recent modifications of a powder gun facility at Caltech have enabled pressure-shear plate impact (PSPI) experiments in a regime of pressures and strain rates that were previously unaccessible. A novel heterodyne diffracted beam photonic Doppler velocimeter (DPDV) has also been developed for simultaneous measurement of the normal and transverse particle velocity histories using the ±1st order diffracted beams produced by a 400 lines/mm diffraction grating deposited onto the polished rear surface of the impacted target plate. We present and interpret the results of a PSPI experiment conducted on a 5 µm thick soda-lime glass sample subjected to a normal stress of 30 GPa and a shear strain rate of 4 · 10^7 s^(–1). Transverse particle velocity measurements reveal a peak shear stress level of 1.25 GPa up to a shear strain value of 2.2, followed by a precipitous drop in stress and complete loss of shear strength.