Crashworthiness study of circular tubes subjected to radial extrusion under quasi-static loading

A structure of circular tubes subjected to radial extrusion with variable geometrical configurations was analysed. In a quasi-static experiment, axial grooves were produced on the circular aluminium tube under the action of indenters, without buckling instability. The energy was absorbed by plastic deformation of the aluminium tube and friction between parts. Deformation and driving force-displacement responses of the circular tube were analysed by way of numerical simulation, which matched the experimental results. Based on the validated finite element (FE) model, the effects of different geometrical configurations on structural crashworthiness were analysed. The results showed that, throughout the deformation stage, a lag was found in force changes in response to the increasing spacing between the aluminium tube and a rib plate and decreasing inclination angle of the indenter. The plastic energy ratio exceeded 60%. The specific energy absorption (SEA) was separately improved by 59.11%, 265.10%, and 75.00% with the increase of the inclination angle and number of the indenters and the decrease of the distance between the indenter and the centre of the tube. The increase in width of the rib plate could not significantly enhance energy absorption effects in the structure. In addition, by utilising the complex proportional assessment (COPRAS) method, it was found that the aluminium tube T3.5 (with wall thickness T of 3.5 mm) exhibited the optimal structural configuration and the best crashworthiness. In conclusion, the use of thin-walled tubes subjected to radial extrusion provide a reference for the development of new energy absorbers.