Determination of fracture mechanics parameters / and C* by finite element and reference stress methods for a semi-elliptical flaw in a plate

摘要

The fracture mechanics parameters J and C* used, respectively, to describe ductile fracture and creep crack growth can be determined either by finite element methods or reference stress techniques. In this paper solutions for a partially penetrating semi-elliptical flaw in a plate subjected to tension and bending loading are considered. Estimates of / and C* are obtained from finite element calculations for a range of work-hardening plasticity and power law creep behaviours and from reference stresses derived from 'global' collapse of the entire cracked cross-section. Comparisons are made with solutions taken from the literature for a range of loading conditions, plate geometries and crack sizes and shapes. Generally it is found that although there are significant variations between the different finite element solutions, satisfactory estimates of / and C* that are mostly conservative are obtained when the reference stress procedure is adopted.