Quasi-static axial compression of triangular steel tubes

To study the collapse mode and energy absorption of triangular tubes, quasi-static axial compression experiments were carried out. Deformation curves and collapse modes were revealed by the experiments. Based on various combinations of the two basic folding elements, four potential collapse modes were proposed and compared to predict the mean crushing force of the tube theoretically. Numerical simulations were applied to suggest a fitted formula of the mean crushing force. Both the analytical and numerical predictions were compared with the experiments to build an effective method to predict the mean crushing force of the triangular tube.

► Progressive collapses of triangular tubes were revealed by experiments.
► Collapse modes were suggested to predict the crushing force of triangular tubes.
► Lower and the upper limits of the mean crushing forces were correctly predicted.