A two-parameter criterion for predicting the fracture location along a surface crack.

The fracture prediction for materials containing surface cracks is not well established. In this paper, a new two-parameter fracture criterion which can predict the location of maximum crack extension along a surface crack front was presented. The surface-cracked specimens with different crack sizes and loads were selected, and the finite element method (FEM) was used to model the J -integral and the equivalent plastic strain ( ε p ) distributions along the crack front for different specimens. And then, in succession, the areas A PEEQ surrounded by the ε p isoline ahead of crack tips under different J -integrals and the unified constraint parameter A p were calculated. Based on the parameter A p , J -integral and the fracture toughness J ref measured in a standard test, the J / ( J ref A p ) , which considered the combined effects of crack driving force and material resistance force, was determined. The critical fracture location is the location for which the J / ( J ref A p ) is a maximum. The results show that for all the specimens, the prediction results obtained by two-parameter criterion are consistent with the measured results obtained by experiments. The J / ( J ref A p ) is a suitable prediction criterion to model the location of the maximum crack extension of surface crack. For comparison, similar predictions were also made using a single-parameter J -integral and A p . [ABSTRACT FROM AUTHOR]