Simulation of Dynamic Crack Growth in Shock Wave Lithotripsy with PDS-FEM

A set of Shock Wave Lithotripsy(SWL) related experimental observations including 3D dynamic crack propagation, reported in literature, are simulated with the aim of understanding the fragmentation of kidney stone with SWL. Extracorporeal shock wave lithotripsy (ESWL) is the fragmentation of kidney stones by focusing an ultrasonic pressure pulse onto the stones. 3D models with fine discretization are used to accurately capture the high amplitude shear shock waves, which play an important role in kidney stone fragmentation. For solving the resulting large scale dynamic crack propagation problem, PDS-FEM is used since it provides numerically efficient failure treatments. With a distributed memory parallel code of PDS-FEM, experimentally observed 3D photoelastic images of transient stress waves and crack patterns in cylindrical samples are reproduced. The experimental and numerical crack patterns are quantitatively in agreement. The results confirm that the high amplitude shear waves induced in solid play a key role in stone fragmentation.