Mutual Influence of Welding Residual Stress Redistribution and Surface Crack Propagation
摘要
The crack propagation life of welded ship structures is considerably influenced by welding residual stresses, which are redistributed as cracks propagate. Therefore, studying the mutual interaction between welding residual stress redistribution and surface crack propagation is crucial for accurately predicting the crack propagation life of welded structures. This research uses TC4 titanium alloy specimens, applying the extended finite element method to investigate the welding residual stress redistribution during surface crack propagation. The cyclic iteration analysis method is proposed to simultaneously consider the redistribution of welding residual stresses and crack propagation. The results show that 1) the welding residual stresses at the surface crack tip and crack depth initially increase, then decrease with crack propagation, and 2) the predicted fatigue crack propagation life, when welding residual stress is not considered, is 2.01 times longer than the corresponding fatigue crack propagation life using the proposed method, which accounts for welding residual stress. In addition, when the welding residual stress is set to a constant value of 0.3 σy, the fatigue crack propagation life prediction becomes overly conservative, yielding only 0.39 times the fatigue crack propagation life predicted based on the mutual influence of welding residual stress redistribution. The fatigue crack propagation life prediction method proposed in this study, which considers the interaction between welding residual stress redistribution and crack propagation, offers a more reasonable approach. It lays the foundation for accurate prediction of fatigue crack propagation life in welded structures.