Effect of initiator, design, and material on crashworthiness performance of thin-walled cylindrical tubes: A primary multi-criteria analysis in lightweight design

• The design with an initiator and higher density of foam had superior performance.
• Multi-criteria analysis to evaluate crashworthiness performance of cylindrical tubes.
• VIKOR in design decision making using both experimental and simulation results.

Two major requirements for crush analysis of thin-walled cylindrical tubes are being lightweight and having good crashworthiness. Thin-walled cylindrical tubes, which are either empty or foam filled, can potentially be used in all vehicles and moving parts such as road vehicles, train, aircrafts, ships, lifts and machinery to protect passengers and the structure itself during impact. This paper discusses an idea of utilizing the initiator on the foam-filled thin-walled circular tubes with stiffened annular rings to increase the specific energy absorption (SEA) and prevent the sudden force applied to the main part of the automotive and its occupants. Effect of initiator, at the top of the foam-filled aluminum tube, different densities of rigid polyurethane foam, and number of annular rings under axial compression were described through energy absorption, crush force efficiency (CFE), and mass of structure. In order to verify the numerical results, a series of quasi-static axial compression tests was performed, and both load–displacement curves and deformation mechanism of the structure were analyzed. The results of multi-criteria decision analysis (MCDA), by incorporating numerical and experimental data, showed that in the considered material and geometry, the design with an initiator, four rings tube, and higher density of foam have superior performance in terms of energy absorption, CFE, and mass. More debate on effect of initiator would help to reach the simultaneous improved crashworthiness structure and lightweight design with greater degree of accuracy in the hope of reducing the occupant injury in a collision.