A two-parameter approach for the analysis of the effect of weld metal on the constraint

Summary

The effect of the mismatched weld metal on the stress field close to the crack tip in an idealized weld joint made up of base metal (BM) and weld metal (WM), with the crack located in WM, parallel to the BM/MW interface, was numerically analysed. The analysis was performed with a J–Q type two-parameter approach with a modified boundary layer (MBL), model, subject to a remote displacement field solely controlled by K_I in order to eliminate the effect of the geometry constraint. The numerical results show that the constraint level decreases for overmatched welds (elastic limit of WM higher than that of BM), and increases for undermatched welds (elastic limit of WM lower than that of BM). The constraint level depends on the degree of mismatch, the width of the weld, and the applied load level.