Fracture analysis of load-carrying cruciform welded joint with a surface crack at weld toe

The load-carrying cruciform welded joint usually fails in the weld root or the weld toe. Determining the failure location in terms of the stress intensity factor (SIF) of the crack at the weld root and the weld toe is an alternative. Various SIF equations have been proposed and incorporated in the British Standard (BS) 7910:2013, including the equations for the welded cruciform joint with a weld toe crack. However, the SIF equations for the weld toe crack are based on 2-D finite element (FE) analysis, which predicts an over-conservative result. In fact, a crack at the weld toe often resembles a semi-elliptical shape. Hence, it is necessary to propose new SIF equations for the load-carrying cruciform welded joint containing a weld toe crack by 3-D FE analysis. The new equations are built up based on multiple regression analysis and the goodness of fit is confirmed via error distribution and statistical analyses by comparing with the FE results. The proposed SIF equations have a wide applicability in the failure analysis of the load-carrying cruciform welded joint.