Analytical model for estimation of energy release rate at mode I crack tip in bi-material of identical steels joined by an over-matched weld interlayer

Abstract

Structure fabricated by welding identical steels or a fractured steel component repaired by steel weld filler of different strength leads to the presence of two interfaces with strength mismatch across them. Mode I crack in such a bi-material upon growing across the weld interlayer experiences the effect of the interfaces that manifests by way of change in crack tip energy release rate from the far field or remote value. The paper presents a strain based analytical model for estimation of the effect of interface over the crack tip. Crack tip energy release rate is determined at all the positions of the crack under SSY or K dominant conditions. The weld interlayer is assumed to be homogeneous and over-matched which possesses higher strength than that of the constituent steels. The modulus of elasticity is same throughout the domain. Edge crack of various discrete lengths is investigated in infinite body under uniform monotonic tension of 150 MPa in plane stress situation for demonstration of the model behavior.