An evaluation of the loading condition on mixed-mode stress intensity factors for CTST specimens made of 2024-T351 aluminum alloy

Abstract

In this research paper, the unstable fracture of 2024-T351 aluminum alloy is studied under a variety of in-plane and out-of-plane mixed-mode loading conditions including pure mode I and pure mode III loadings. A recently proposed loading device with compact tension shear tearing (CTST) specimens is employed for performing fracture experiments. Three-dimensional finite element analyses using the M-integral approach are conducted to derive the stress intensity factors distributions along the crack front for different mixed-mode configurations. The numerical results reveals that the coupled effect of modes II and III can be observed under mixed-modes I/II, I/III and I/II/III loading conditions. Furthermore, the values of stress intensity factors at the midsection of the specimens are used to predict the critical loads based on different mixed-mode criteria. A good consistency is observed between the theoretical predictions of the criteria and the experimental results for different loading conditions.