Influence of laminate code and curing process on the stability of square cross-section, composite columns – Experimental and FEM studies

Abstract

The objective of this research is to investigate the influence of the laminate code and autoclaving process parameters on the buckling and post-buckling behaviour of thin-walled, composite profiles with square cross-section. A compression of profiles with the following dimensions was investigated: (width × height × thickness) 80 mm × 80 mm × 1.2 mm and length equal to 240 mm. The laminates were cured in two autoclaving processes: the nominal process on an empty aluminium mandrel and slow curing process on a full aluminium mandrel. Five different laminate codes were inspected – two symmetric and three anti-symmetric ones with respect to the midplane of the laminate. In total, 40 samples were inspected. The results were compared with two FE models. The first did not include the residual stresses in the material while the second did. A comparison of experimental data with the results of FE modelling proves that residual stresses significantly contribute in the buckling and post-buckling behaviour of thin-walled laminated structures with closed cross-section. Their occurrence has a positive effect on the stability of the columns. The study also covers the discussion about the failure loads of the considered columns.