Stress state failure analysis of thin-walled GLARE composite members subjected to axial loading in the post-buckling range

Abstract

The paper investigated the load-carrying capacity and the participation of stress components in the failure analysis of top-hat-shaped composite columns subjected to uniform compression. GLARE members were axially compressed in laboratory tests employing a static testing unit. Failure tests were monitored in the full load range using the digital image correlation (DIC) system, which enabled visualization of full-field displacements and strains. Simultaneously, FEM numerical simulations were carried out to estimate the load-carrying capacity of the top-hat-shaped sections based on the nominal stress state in both the non-degraded and degraded composite models. In the latter, the material property degradation method (MPDG) allowed a progressive lowering of the material stiffness based on the presumed damage variables. Failure initiation in composite plies was monitored in FE simulations based on Hashin and Puck failure criteria. Stress state analysis was performed to investigate the participation of stress tensor components in the failure function of selected failure criteria. This enabled the identification of critical stresses contributing to aluminum plastic deformation and intra-laminar failure mechanisms that led to the composite fracture. The results of the numerical simulations were found to be in high agreement with the experimental evidence.