Abstract

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/WM interface, was numerically analyzed. 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 KI in order to eliminate the effect of the geometry constraint. The numerical results show that the constraint level decreases for overmatched welds (yield stress of WM higher than that of BM), and increases for undermatched welds (yield stress of WM lower than that of BM). The constraint level depends on the degree of the mismatch, on the width of the weld, and on the applied load level.