Failure assessment of thin-walled FML profiles during buckling and postbuckling response

The paper discusses nonlinear buckling and failure analysis of FML thin-walled structures under axial compression. Study was carried out on Fibre Metal Laminates (FMLs) made of alternating thin layers of aluminium and glass fibre-reinforced unidirectional prepreg. Various 3/2 symmetrical lay-ups were investigated and depending on fibres alignment 7 stacking sequences of FML were considered when subjected to axial compression in laboratory buckling tests. The behaviour of thin walled compression members was investigated with main focus on buckling and post-buckling response and various failure mechanisms. Experimental procedures included macroscopic and microscopic examination performed by means of stereoscopic, optical and scanning electron microscope (SEM). The results of experimental investigations were compared with finite element simulations wherein Tsai-Wu, Hashin and Puck failure criteria were applied. Failure assessment by FEM included also an attempt to estimate particular regions of laminate's fracture within buckling and post-buckling state.