Search Results

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.

Fatigue behavior of dissimilar Al/Fe spot friction welds between aluminum 6000 series alloy and coated steel sheets in lap-shear and cross-tension specimens is investigated based on experiments and three-dimensional finite element analyses. Micrographs of the welds after failure under quasi-static and cyclic loading conditions show that the Al/Fe welds in lap-shear and cross-tension specimens failed along the interfacial surface. Three-dimensional finite element analyses based on the micrographs of the welds before testing were conducted to obtain the J-integral solutions at the critical locations of the welds under lap-shear and cross-tension loading conditions. The numerical results suggest that the J-integral solutions at the critical locations of the welds can be used as a fracture mechanics parameter to correlate the experimental fatigue data of the Al/Fe spot friction welds in lap-shear and cross-tension specimens.