Numerical Investigations on the Effects of T-Stress in Mode I Creep Crack

Abstract

The effects of [Formula: see text]-stress on the stress field, creep zone and constraint effect of the mode I crack tip in power-law creeping solids are presented based on finite element (FE) analysis in the paper. The characteristics of the crack tip field in power-law creep solids by considering low negative [Formula: see text]-stress and high positive [Formula: see text]-stress are studied in the paper. The differences of [Formula: see text]-stress effect on the crack tip field between power-law creeping solids and elastoplastic materials are also clarified. A modified parameter is proposed to characterize the influence of [Formula: see text]-stress on creep zone. The constraint parameter [Formula: see text] under both small-scale creep and large-scale creep with various [Formula: see text]-stresses for the modified boundary layer (MBL) model and various specimens with different crack depths are given. The applicability and the limitation of the MBL model for creep crack are also investigated. The inherent connection between [Formula: see text]-stress and [Formula: see text]-parameter is discussed. The investigations given in this paper can further promote the understanding of [Formula: see text]-stress effect and constraint effect on the mode I creep crack.