Fatigue strength in laser welding of the lap joint

Finite element analysis and fatigue test are performed to estimate the fatigue strength for the laser-welded lap joint. Concentrating on the application of design and manufacturing technology using the laser-welded lap joints, the residual stress and welding direction of the laser-welded lap joint have to be considered in relation to its fatigue strength. After three-dimensional modeling for the longitudinal direction parallel to fatigue load and transverse direction perpendicular to that, residual stress fields in laser-welded lap joint are calculated using thermo-elastic-plastic finite element analysis. Then the equivalent fatigue stress with residual stress effect is obtained. In order to ensure reliability of calculated fatigue strength, fatigue test is performed. The calculated and experimental results showed good agreement. The fatigue strength in the transverse direction welding is higher than that of longitudinal direction welding. (C) 2003 Elsevier B.V. All rights reserved.