Unified Characterization of Crack Growth Parameters based on Plastic Stress Intensity Factor

Abstract

The aim of this work is to study and represent the combined in-plane and out-of-plane constraint effect on the material fracture resistance characteristics under static and fatigue loading. Subjects for numerical and experimental studies are three-point bending and compact specimens under static loading as well as cruciform specimens under cyclic biaxial and mixed mode loading. For the static tests experimental specimen geometries considered (SENB and CS), the elastic constraint parameters and the parameter governing of the plastic stress field In distributions are obtained as a function of both the specimen thickness, the dimensionless crack length and crack length. For the fatigue tests specimen configurations (CCS) the T-stress and the numerical constant In are calculated with the variation of biaxial stress ratio and full range mode mixity. A method is also suggested for calculating the plastic stress intensity factor for mixed-mode I/II loading based on the T-stress and power law solutions. It is found that the plastic stress intensity factor accounting for the in-plane and out-of-plane constraint effect can be applied to characterize the fracture toughness and the multiaxial crack growth rate for a variety specimen geometries.