Effects of residual stress and geometry on crack kink angles in graded composites

Effects of residual stress, geometry and applied load on the stress intensity factors of cracks in discretely layered, graded composites were investigated using finite element techniques. Elastic gradient profiles introduce mixed mode conditions for cracks oriented perpendicular to the gradient. Residual stresses further affect the in-plane stress intensity factors such that the amount of mode-mixity depends on the applied load. The effect of residual stress and applied load on the mode-mixity depends on the specimen geometry. Implications of the residual stress and geometric-load effects on the predicted crack kink angle are discussed.