Effect of LSP Generated Residual Stresses on Fatigue Crack Propagation in Thin Panels

This work deals with the prediction of the residual stress field after Laser Shock Peening process on aluminum coupons by means of Finite Element (FE) modelling. The commercial software Abaqus Explicit has been used. The work includes investigation on mesh sensitivity, tuning and optimization of a simplified model by using physical (Kinematic Hardening material model) parameters. The models have been validated by comparison with experimental results on simple specimen with multiple peening. Moreover, the effect of the LSP treatment on thin aluminum panels has been evaluated. Starting from the numerical assessment of the self-balancing residual stress distribution along the entire panel width, the fatigue crack growth through the panels has been analytically estimated and compared with experimental results. The comparison highlights the sensitivity of the fatigue crack propagation life to the selected LSP pattern configuration which has to be accurately setup in order to exploit the full potentiality of the LSP process in increasing the fatigue life and avoid undesired reduction of the component performances.