An analysis of fracture under biaxial loading using the non‐singular T‐stress

Finite element analysis using a two‐dimensional modified‐boundary‐layer approach wasused to model the effects of biaxial loading on crack tip stress fields. Loadings wereapplied corresponding to an elastic KI field, non‐singular T‐stress and a biaxial stress.For through‐thickness cracks the T‐stress inherent in the specimen geometry isaugmented by the external biaxial stress. For surface‐notched specimens the biaxialstress acts out of the crack plane. This effect was modelled with generalized plane strainelements. Results were analysed using the Anderson‐Dodds approach for cleavage andthe Beremin model in the ductile regime. Biaxial loading is predicted to have a largeeffect on the toughness of a through‐thickness crack but little effect on a surface crack.Experimental results from a previous series of large‐scale biaxial fracture tests aregenerally consistent with these predictions.