Fatigue Behavior of Laser Welds in Lap-Shear Specimens of High Strength Low Alloy (HSLA) Steels

Fatigue behavior of laser welds in lap-shear specimens of high strength low alloy (HSLA) steels is investigated based on a fatigue crack growth model. Fatigue experiments of laser welded lap-shear specimens were conducted. Analytical global stress intensity factor solutions are developed and compared with finite element computational results. A fatigue crack growth model based on the analytical local stress intensity factor solutions of kinked cracks and the Paris law for crack growth is then adopted to estimate the fatigue lives of the laser welds under cyclic loading conditions. The estimated fatigue lives are compared with the experimental results. The results indicate that the fatigue life predictions based on the fatigue crack growth model are slightly longer than the experimental results. The results of the predictions indicate that consideration of the finite length of the kinked crack in the fatigue crack growth model is needed to predict the experimental results more accurately.