Influence of Residual Stress on Stress Intensity Factor Estimation of Multiple Cracks in a Dissimilar Welded Joint

Influence of residual stresses on mixed mode Stress Intensity Factor (SIF) of dissimilar (steel and aluminium) butt welded joint is investigated numerically. Opposite cracks with various crack depth ratio, crack aspect ratio and heat fluxes were considered. The geometry correction factor was calculated by considering the effect of mode-II and mode-III fracture. For short cracks [(a/d) = 0.1] as the residual stress increases, SIF for steel decreases and increases for aluminium at crack surface region [(P/P0) = ±1]. When the crack depth ratio increases, SIF for both materials decreases along the crack front due to relieving of stresses at higher depths [(a/d) = 0.4]. Non uniform crack opening was observed along the crack front and in between the front side and back side cracks.