Response of cracks to impact by caustics

A study of the behaviour of notched plexiglas specimens under stress pulses created from an air-gun was undertaken. It was concluded that the initial notch is propagated by steps under the action only of tensile stress pulses, while the compressive stress pulses do not have any influence on crack propagation. It was also found that the maximum crack propagation velocity depends on the magnitude of the applied stress pulse, as well as on the initial notch length. Furthermore, the dependence of the crack-tip stress intensity factor on the crack propagation velocity was established and the critical strain energy release rate was determined. Finally, a comparison of the results of the present paper with the corresponding theoretical or experimental data of previous investigations was made.