Numerical study for the effect of shape of additional weld on fatigue strength in out-of-plane gusset welded joint

Fatigue crack is often initiated around weld toe, mainly caused by high stress concentration. Various techniques for improving the fatigue strength of joints have been proposed up to the present. Additional welding is known to be one of the effective techniques to improve the fatigue life of welded components. Recently, the authors have conducted fatigue tests on joints with additional weld. The tested welded joints were fabricated with different additional welding conditions. The tests revealed that smaller flank angles and bigger weld toe radii were obtained under certain additional weld conditions and the fatigue tests indicated that fatigue strength of out-of-plane gusset was remarkably improved by additional welding. In this study, 3D finite element (FE) analyses were conducted based on the in-house experimental campaign carried out to characterize the effect of additional welding on fatigue life. The crack initiation and crack propagation simulations were conducted using elastoplastic and linear fracture mechanics analyses, respectively. The results show that an additional weld treatment reduced remarkably the stress concentration at weld toe, leading to longer fatigue life. © 2020 Japan Welding Society. All rights reserved.