Experimental investigation of the lateral crushing behaviour of short sandwich tubes

Short tubes are common structural components for energy absorption. Sandwich tubes are expected to enhance the energy absorption capacity. To this end, experiments were conducted to investigate the lateral crushing of short sandwich tubes in this paper. Twenty eight sandwich tubes and twenty four monolithic aluminium tubes with a length of 50 mm and different diameter to thickness ratios were laterally crushed by an MTS machine with a fixed displacement rate of 2 mm/min. Their deformation histories and load-displacement curves were obtained. The deformation characteristics of short sandwich tubes were found to be bending dominated with plastic hinges, accompanied with crushing of the core. Three major collapse patterns were observed and summarized in terms of geometric features. They were simultaneous collapse, tear facture collapse and sequential collapse. Four major factors that influenced the collapse load in plastic collapse stage were investigated, namely glue effect, average radius of curvature, thickness ratio of inner and outer tubes and thickness of core. It was observed that the following factors increased the total energy absorption capacity of sandwich tubes: applying bonding, decreasing of average radius of curvature, significantly increasing of core thickness. Increase of thickness ratio of inner and outer tubes changed the deformation patterns which resulted in a decrease of collapse force at the earlier stage and enhanced collapse force later on.