Interaction of Mechanical Heterogeneity and Residual Stress on Mechanical Field at Crack Tips in DMWJs

Abstract

The interaction between the mechanical heterogeneity and the residual stress in dissimilar metal welded joints (DMWJs) leads to a complex mechanical field of crack tips, which strongly affects stress corrosion cracking (SCC) behaviors. A dual-field coupling model was established by using the user-defined field (USDFLD) and the predefined stress field method based on the elastoplastic finite element method in this study. Thus, the mechanical heterogeneity and the residual stress of the DMWJ are realized. The influence of the interaction between the mechanical heterogeneity and the residual stress on the mechanical field of crack tips at different locations was investigated. The results show that the mechanical heterogeneity causes the stress and strain distribution on both sides of the crack tip asymmetry. And the residual stress affects the magnitude of the stress and strain around the crack tip. The variation trend of the stress and strain along the crack propagation with crack length is basically the same as that of the residual stress. However, the stress and strain distributions are slightly lagging behind the residual stress distribution due to the redistribution of the residual stress caused by the crack propagation. In addition, the stress and strain range of cracks at different positions with crack length are also different.

Stress and Strain State Analysis of Crack Front in Dissimilar Metal Welded Joints with Dual Field of Mechanical Heterogeneity and Residual Stress

“…erefore, the variation trend of the tensile stress at the crack front does not completely coincide with the original distribution of residual stress. is phenomenon was studied in detail in [14]. is figure can better describe the effect on tensile stress at the crack front of non-uniform residual stress during the crack growth.…”

“…However, under the interaction of mechanical heterogeneity and the residual stress, stress and strain states at axial direction SCC crack front with different crack locations and depths in the DMWJ have not been investigated and understood. Rapid advances in finite element software make it an effective tool for crack analysis [14][15][16][17].…”

A novel method for predicting local plastic mechanical properties of metal structures by integrating microstructure and instrumented indentation technique

“…Notably, instrumented indentation technique (IIT), as a non-destructive method, has demonstrated a strong correlation with standardized mechanical testing procedures [5][6]. Furthermore, IIT facilitates in-site evaluations of in-service structural materials, increasingly emerging as a pivotal technique for micro/nanoscale mechanical property assessments [7]. Particularly, IIT offers inherent advantages in evaluating the mechanical behavior of heterogeneous material welded structures.…”