Simulation of Laser Shock Wave Propagation and Dispersion in SHPB

Abstract

Laser shock wave oscillation caused by lateral inertia effects of Hopkinson bar in large-diameter SHPB apparatus, and the geometry dispersion effect, particularly, the rise time of the stress wave in different diameters and lengths of Hopkinson bar were investigated. The three-dimensional model of member bar is established by the finite element analysis software ABAQUS, and the different shapes pressure pulses including rectangular, triangular and Gaussian pulses induced by laser shock have been loaded on the end face of the bar, respectively. Results indicate that the triangle pressure pulse and Gaussian pressure pulse show less dispersion effect than rectangle stress pulse on wave shape, and Gaussian stress pulse can keep the morphology better and reduce the dispersion effect more effectively than triangle stress pulse in the propagation process. In addition, as the bar diameter increases and the distance of the propagating stress wave raises, wave oscillation enhances significantly in the bar, the same as the rise time of stress wave increases gradually and the maximum stress also has a certain degree of attenuation, which have influence on laser shock processing or forming.