Numerical and experimental investigations of the post-buckling behaviour of square cross-section composite tubes

Abstract

The buckling and post-buckling behaviour of thin-walled square cross-section tubes subjected to static compression is presented. The columns under consideration were made with the autoclaving technique of eight layers of a glass fibre reinforced polymer unidirectional prepreg tape. Six different arrangements of layers were taken into account. The following experimental data were collected: force–displacement relations obtained from a Zwick/Roel universal testing machine, strains at chosen points of the tube measured with a strain gauge technique, a map of deflections obtained with a non-contact 3D optical method (Aramis System, made by GOM company). All those results were used to determine buckling load and equilibrium paths in the pre- and post-buckling range. A numerical model of the analysed tube was prepared with the ANSYS software. A linear and nonlinear buckling analysis was performed. The experimental results were used to validate the proposed FEM model. An influence of the layer arrangement on the buckling and post-buckling behaviour, differences between the numerical and experimental results and the methods employed for buckling load determination are discussed.