Enhancing Structural Analysis of Dissimilar Metal Spot-welded Lap-Joints Utilizing Thermal Strain Generation Algorithm

This study presents a computational framework for fatigue life prediction in spot-welded joints by integrating thermal strain-induced prestress with the Morrow mean stress correction model. The approach captures the effects of residual stresses arising from differential thermal expansion, which are especially critical in dissimilar material joints. Finite element simulations were performed on tensile-shear (TS), single-lap (SLJ), and modified tensile-shear (MTS) specimens. Validation against over experimental data from the literature showed that incorporating thermal prestress significantly improved prediction accuracy, with most results falling within a ±5% error band. The unified framework demonstrated reliable performance across both similar and dissimilar configurations without geometry-specific recalibration. The proposed method offers an efficient and generalizable tool for fatigue assessment in welded structures common to automotive and aerospace applications.