Effect of thickness on fracture properties and a concept of equivalent thickness

摘要

Thickness dependence of the one-parameter-based fracture toughness has been well recognizedand widely studied.However,it is still a challenge to predict the fracture of structures withcurved cracks from the fracture toughness data obtained from the standard through-the-thicknesscracked specimens.The complicated three-dimensional (3D) stress fields near the crack front playa vital role in the fracture strength of materials.Based on a systematical numerical study of the3D stress fields near various crack tips and comparison with that of ideal through-the-thicknesscracks,an equivalent thickness conception for curved cracks is proposed from the viewpoint of outof-plane constraint,and semi-analytical solutions for the equivalent thickness of various typicalcracks such as through-the-thickness crack,quarter elliptic corner crack,elliptic surface crackand embedded elliptic crack are obtained.