Dent-inert post-buckling behavior of liquid nanofoam-filled tube

Abstract

Thin-walled tubes have been widely used in crashworthiness applications such as automotive and aerospace industries. However, inevitable structural imperfections in the tube wall impose adverse effects on the energy absorption performance of the tube. Here, we have employed a fluid-like and highly compressible material, i.e. liquid nanofoam (LN), as a filler to suppress the negative impact of structural imperfection. The mechanical performance of empty tubes and LN-filled tubes (LNFT) with different dent imperfections has been evaluated by quasi-static uniaxial compression tests. Results show that empty tube is susceptible to structural imperfection, as a v-shaped dent with 1.5 mm depth reduces the energy absorption capacity by about 20%. In contrast, the mechanical performance of LNFT is insensitive to the existence and depth of the dent. The enhanced imperfection insensitivity of LNFT is due to the intimate liquid-solid interaction at the LN filler and the tube wall interface, which effectively suppresses the curvature growth of the dent and the localized folding. The findings provide an efficient approach for designing and engineering thin-walled energy absorption devices that are resilient and of high energy absorption capacity. • Negative impact of structural imperfection on regular thin-walled tube is studied. • Novel liquid nanofoam-filled thin-walled composite structure is developed with 100% imperfection resistance. • Detailed tube wall buckling mode of both tubes is revealed. • The imperfection inertness of LNFT is due to the liquid-solid interaction at the filler-tube wall interface.