Axial crushing behaviors of buckling induced triangular tubular structures

To reduce the initial peak force (IPF) and improve the crushing force efficiency (CFE) of tubular energy absorbers, buckling induced tubes (BITs) were designed based on modal analysis of straight-walled triangular tubes. The crushing mechanism of the BIT under quasi-static compression was revealed through finite element analysis (FEA) and theoretical analysis. It is found that the BIT can be folded according to specific mode by cleverly presetting the convex-concave structure form. The larger is the amplitude of the buckling wave, the smaller is the IPF, as well as the mean crushing force (MCF). But the CFE is greatly improved. Compared with straight tubes, high-order mode BITs have lower IPF but greater MCF, CFE and specific energy absorption (SEA). A simplified model based on Shanley model was proposed to predict the IPF of the BIT. The MCF was predicted by improved super folding element (SFE) and simplified super folding element (SSFE) models. End buckling induction mechanism is introduced as an efficient way to reduce the IPF, but keep the MCF and enhance the CFE simultaneously.