Methods of predicting the fatigue lives of laser-beam welded lap welds subjected to shear stresses

One prerequisite for reliably predicting the fatigue lives of joined components in complex products such as a vehicle is that not only the local stresses but also the local stressability of the material are known to a sufficient extent. This contribution presents the structural-stress concept, the structural stress taking account of geometrical effects and the notch-stress concept as methods of describing the local stresses on a laser-beam weld subjected to shear loads. The stressability is obtained by assigning the stress-cycle lines to the respective local stresses. If the suitable local stresses are chosen, this results in the stressability as a pure material property. On the basis of bearable loads and bearable local stresses, laser-beam stitch welds are compared with resistance spot welds.