Progressive failure analysis of thin-walled Fibre Metal Laminate columns subjected to axial compression

Abstract

The subject of the paper is the progressive failure analysis (PFA) of thin-walled Z-shape cross section members subjected to axial compression. This study concerns angle-ply multi-layered Fibre Metal Laminates (FMLs) which consist of alternating thin layers of aluminium and glass fibre-reinforced unidirectional prepreg. Laboratory damage tests were performed by the static testing unit that provided displacement control loading. Experimental results were compared with FEA wherein based on the profile's nonlinear stability investigations the failure analysis was performed. Nonlinear FE simulation combined with available progressive failure mechanics allowed to predict the initiation and propagation of the multi-failure modes within composite material. Hashin failure criterion was used to monitor the initiation of damage, whereas material degradation method (MPDG) was applied in FRP layer to define the damage evolution law. Damage variables were specified according to FEM modelling procedures in order to control material stiffness reduction after damage initiation. For aluminium layers the J2 plasticity model was employed. Progressive failure assessment by FEM allowed to estimate the post-buckling equilibrium paths and damage modes with particular regions of laminate's fracture that were found to be in a good agreement with experimental evidences.