The fracture of glass under high-pressure impulsive loading

Abstract

A series of planar shock-wave experiments were performed with glass and fused quartz. The states of shock-compressed material were probed by rarefaction waves from the rear free surfaces of the samples. Formation and propagation of failure waves were observed in shock-compressed glass. The failure wave nucleates initially at the surface of a compressed glass sample and then propagates into the sample with velocity decreasing from 2 to 1 km/s. The matter behind the failure wave front has no tensile strength and has somewhat lowered impedance. Probably, discrepancies in the results of spall strength measurements of glass reported by various investigators is explained by the appearance of a failure wave. The spall strength of glass is found equal to at least 5 GPa from our experiments, in which the failure wave was taken into consideration in terms of the ratio of the thickness of impactor and target.