Stress Intensity Factors and T-Stress Solutions for Mixed-Mode Compact-Tension-Shear (CTS) Specimens With Slanted Propagating Cracks

Abstract

Abstract More and more attention has been paid to the problems of fatigue fracture in mixed fracture modes, and researchers have developed a variety of laboratory specimen types. Among them, the Compact-Tension-Shear (CTS) specimen with its loading device has been widely used in mixed-mode I&II fatigue crack growth (FCG) experiments. In this paper, for CTS specimen with slanted propagating crack, the variation of stress field parameters including stress intensity factors (SIFs) and T-stresses were investigated through three-dimensional finite element (FE) analysis. The results show that the direction of crack initiation tends to make KII vanish and then the crack propagates in a mode I dominant manner even under mode II dominant loading angles. In addition, among the considered range of geometries, T11 is greatly influenced by the initial crack length ratio, the slanted propagating crack length ratio and the loading angle, but rarely by the specimen thickness ratio. However, T33 as an out-of-plane constraint parameter, is subject to the coupling effects of in-plane geometries, out-of-plane geometries and the mixed-mode loading. The conclusions obtained in the current work will provide usable constraint-related crack front stress field parameter solutions for the analysis of fatigue crack propagating behavior in mixed fracture mode.