Simulation of multiple laser shock peening of a 35CD4 steel alloy

Laser shock peening (LSP) treatment of a metal surface is proving to be superior to conventional treatments such as shot peening in many engineering products. The LSP process, which introduces compressive residual stresses deep into a metal alloy, has led to some impressive results such as a significant improvement in fatigue life. This paper focuses on applying finite element analyses, instead of a complicated experimental procedure, to predict the development, magnitude and distribution of residual stresses induced by multiple LSP impacts on a metal alloy, 35CD4 30 HRC steel. The single peening results calculated by the finite element method are correlated well with the available experimental results. The simulated results clearly show that the compressive residual stresses induced by the multiple LSP impacts can be driven deeper below the surface of target than that by the single LSP impact. The simulated results also reveal that adjusting the laser spot size appropriately in a LSP process can result in an increase in compressive residual stresses in the target.