Dynamic Effects of Liquids on Crack Growth Leading to Catastrophic Failure in Glass

Crack growth in glass plates, up to supercritical velocities, was produced by controlled strain, velocity being measured continuously by superimposing a tuned‐frequency sonic signal during cracking. Cracks, which were accelerated to supercritical velocity in the presence of water, showed an order of magnitude jump in velocity and an associated cavitation scarp on the crack surface marking the onset of catastrophic failure. The crack velocity immediately preceding catastrophic failure is termed the critical velocity. Measurement to the cavitation scarp was suggested as a means to determine the size and shape of critical flaws in bend‐test specimens. The velocity jump was explained in terms of a drag effect which may result from crack topographical features as well as viscous drag forces. A model involving liquid cavitation was formulated to predict critical velocity as a function of environmental parameters. Experiments in some aqueous solutions suggested preferential transport of water to the crack tip.