Shear-wave generation from cavitation in soft solids

Abstract

The formation and dynamics of cavities in liquids lead to focusing of kinetic energy and emission of longitudinal stress waves during the cavity collapse. Here, we report that cavitation in elastic solids may additionally emit shear waves that could affect soft tissues in human bodies/brains. During the collapse of the cavity close to an air-solid boundary, the cavity moves away from the boundary and forms a directed jet flow, which confines shear stresses in a volume between the bubble and the free boundary. Elastographic imaging and high-speed imaging resolve this process and reveal the origin of a shear wave in this region. Additionally, the gelatin surface deforms and a conical crack evolves. We speculate that tissue fracture observed in medical therapy may be linked to the non-spherical cavitation bubble collapse.