Nanosecond Shock Wave-Induced Surface Acoustic Waves and Fracture at Fluid-Solid
I investigate the generation and propagation characteristics of leaky Rayleigh waves (LRWs) by a spherical shock wave incident on a glass-water boundary both experimentally and numerically. The maximum tensile stress produced on the solid boundary was attributed to the dynamic interaction between the LRWs and an evanescent wave generated concomitantly along the boundary. The resultant tensile stress field drives the initiation of pre-existing microcracks and their subsequent extension along a circular trajectory, confirmative with the direction of the principal stress on the boundary. We further demonstrated that this unique ring-like fracture, prevalent in damage produced by high-speed impact, can be best described by the Tuler-Butcher criterion for dynamic brittle failure, and the orientation of the ring fracture extension into the solid also follows closely the trajectory of the local maximum tensile stress distribution.
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