Massive parallel laser shock peening: Simulation, analysis, and validation

Laser shock peening (LSP) is a transient process with laser pulse duration time on the order of 10 ns, real time in situ measurement of laser/material interaction is very challenging. LSP is usually performed in a massively parallel mode to induce uniform compressive residual stress across the entire surface of the workpiece. The purpose of this paper is to investigate the effects of parallel multiple laser/material interactions on the stress/strain distributions during LSP of AISI 52100 steel. FEA simulations of LSP in single and multiple passes were performed with the developed spatial and temporal shock pressure model via a subroutine. The simulated residual stresses agree with the measured data in nature and trend, while magnitude can be influenced by the interactions between neighboring peening zones and the locations of residual stress measurement. A design-of-experiment (DOE) based simulation of massive parallel LSP were also performed to determine the effects of laser intensity, laser spot size, and peening spacing on stresses and strains. Increasing the laser intensity increases both the stress magnitude and affected depth. The use of smaller laser spot sizes decreases the largest magnitude of residual stress and also decreases the depth affected by LSP. Larger spot sizes have less energy attenuation and cause more plastic deformation. Spacing between peening zones is critical for the uniformity of mechanical properties across the surface. The greatest uniformity and largest stress magnitudes are achieved by overlapping of the laser spots. 2007 Elsevier Ltd. All rights reserved.