Computational simulation of fatigue crack growth and demonstration of leak before break criterion

A thick plate with a semi-elliptical surface crack subjected to remote tension and tension fatique loading is considered for the analysis. In the present study the material is assumed to have variable fracture toughness in the surface and thickness directions. Material with isotropic fracture toughness is also considered. The developed three dimensional finite element code which has the capability to handle singularity and evaluate fracture parameter based on force method is used to characterise the fatigue crack growth. Parametric study involving various initial crack sizes is carried out and Foreman's equation is used to predict the crack growth. Various regions viz. break, leak before break are obtained.