Bio-inspired multi-cell tubular structures approaching ideal energy absorption performance

The energy absorption potential of conventional thin-walled tubes is compromised by the long-wavelength folding lobes, which result in a mean crushing force that is much smaller than their yield strength. Here, inspired by the characteristics of the skeletal of the glass sponge, a new thin-walled multi-cell tubular structure with modified face-centered cubic (MFCS) cross section is proposed. The compression behaviors and energy absorbing capacity of the proposed structure were compared with those of the traditional multi-cell tube through finite element simulation and experimental tests. Compared with the traditional multi-cell tubes, the proposed MFCS structure exhibits micro-folding lobes with shorter wavelength, resulting in larger energy absorption, higher energy absorption efficiency and a more stable and controllable deformation mode, with the mean crushing force almost reaching that of an ideal energy absorber. Moreover, the effects of the geometric coefficient of MFCS multi-cell tube on the energy absorption performance and deformation pattern were studied parametrically. Through the bionic design, extraordinary energy absorbing performance is achieved, providing guidance for future design of lightweight structures with unprecedented mechanical properties.