Load carrying fillet-welded cruciform joints have two fatigue crack initiation points. They are located in the weld toes and weld roots where high stress concentrations occur. Which of the two serves as the initiation point depends on the weld leg length, plate thickness, and weld penetration, and the mechanism concerned is easily understood. Some experimental results indicate that the fatigue crack initiation point is also affected by the magnitude of the stress range. The reason for this phenomenon remains rather obscure. To establish this reason, the present research study is intended to clarify the relationship between the stress range level and fatigue crack initiation point changes and to quantify the effects of the weld leg length and penetration depth on the fatigue crack initiation point. Fatigue tests of welded joint specimens, thermal elastic-plastic finite element method (FEM) analyses of welding residual stresses and fatigue crack propagation analyses considering the residual stress are performed.
展开▼
