Influence coefficient based fracture parameter modification factor in a cracked T-butt welded joint

Abstract

An influence coefficient based modification factor (μk) method and its regression formulae are proposed. The μk can be used to calculate the stress intensity factor (SIF) in a cracked T-butt welded joint under arbitrary stress distribution. By multiplying μk with the SIFs of a flat plate obtained by numerical influence function method (NIFM), mixed-mode SIFs (MM-SIFs) for a T-butt joint can be readily evaluated. T-butt joints with semi-circular surface cracks are employed in the numerical examples. The MM-SIFs calculated by the μk method were verified against those computed under direct membrane loading, and under welding residual stress conditions. An adequate agreement was achieved between the solutions given by the proposed μk method and the reference numerical analyses. Therefore, the MM-SIFs of surface-cracked T-butt joints under arbitrary stress distributions can be evaluated using the developed μk formulae.