Energy absorbing ability of rectangular self-similar multi-cell sandwich-walled tubular structures

Thin-walled tubes (TWTs) have been widely applied as energy absorbers in engineering. The energy absorbing property of rectangular TWTs can be substantially enhanced by changing the ultra-thin solid walls into sandwich walls. Sandwich wall has great bending rigidity and it improves the energy absorption through two aspects: shortening the wave length or improving the plastic bending moment. Competition of these two mechanisms endows the rectangular sandwich-walled tube (SWT) with excellent energy absorbing ability and the best performance is achieved when the two mechanisms appear simultaneously. Mean crushing force (MCF) of the rectangular SWT could be 2.5 times of that of the TWT. The MCF of optimally designed rectangular SWT is even greater than the yield load of the tubular structure.