Effect of Laser Shock Peening on the Fatigue Behavior of Thin Aluminum Panels

In order to evaluate the effectiveness of the Laser Shock Peening (LSP) in reducing the fatigue related problems in metallic structures, thin aluminum specimens have been peened along straight patterns perpendicular to the crack. Despite of the induced compressive residual stresses, the tests showed a negative effect of the LSP on the fatigue crack propagation performances. Starting from the numerical assessment of the self-balancing residual stress distribution and the measurements of the residual stresses, the fatigue crack growth has been analytically evaluated and compared with experimental results. The comparison highlights the sensitivity of the crack propagation to the width of the LSP treated strip and its position relative to the crack.