Fatigue damage analysis of welded structures based on continuum damage mechanics

In this study, the fatigue damage analysis and life prediction of welded structures are carried out by using continuum damage mechanics. For high cycle fatigue, it is considered that plastic deformation and damage occurs at a microscopic scale. Therefore, a two-scale model presented by Lemaitre is introduced to evaluate the high cycle fatigue damage evolution. As it is difficult to identify the parameters directly at the micro scale, the identification method is proposed to obtain the reliable material parameters for weldment. In order to consider the effect of residual stress on fatigue behavior of welded joints, the inherent strain method is applied to determine the residual stress. The analytical results by the proposed method are compared to experimental results and it is confirmed that the proposed method could give the reliable fatigue lifetime of welded structures.