A multi-method coupled approach to simulate crack growth path and stress-strain field at the tip of the growing crack in the dissimilar metal welded joint

This study investigates the crack growth path and the stress-strain field at the tip of the growing crack within various locations of a dissimilar metal welded joint (DMWJ), incorporating an in-depth analysis of the joint's heterogeneous material properties and microstructure. Several novel finite element simulation methods are employed. Among these, a "user-defined field" is developed to achieve a continuous transition of material mechanical properties within local regions of the joint. Subsequently, the crack growth path within different parts of the joint is analyzed using the extended finite element method (XFEM). Upon determining the crack growth path, the De-bond method, through a sub-model focusing on the local regions of the crack tip, is utilized to analyze the stress-strain field at the tip of the growing crack under constant load conditions. The findings reveal that the mechanical heterogeneity at the local region of the welded joint impacts the crack growth path. Stress corrosion cracking (SCC) tends to favor the side with higher yield strength. Materials with higher yield strength typically exhibit lower plastic deformation and crack resistance, resulting in a greater driving force for crack propagation and making SCC more prone to propagation. Significant residual stress and strain can be observed along the path after growth. The primary aim of this study is to establish a coupled multi-method approach, integrating XFEM and the De-bond method, to accurately predict the crack growth path and analyze the stress-strain field at the tip of the growing crack. This information could be instrumental in assessing the integrity of DMWJs.