Bionic polycellular structures for axial compression

Abstract

Many traditional thin-walled structures have the disadvantages of excessive force drop after the initial peak and large structural mass (SM). Inspired by bamboo and lotus root, hexagonal, pentagonal, quadrilateral and triangular polycellular structures (PSs) are proposed in this work to overcome these shortcomings. Their energy absorption, deformation modes and equivalent densities under axial compression are studied. For PSs with connecting plates, the crushing mode of cells is analyzed, and many interesting deformation modes of these PSs such as double-headed axe, progressive collapse and single-headed axe shapes are presented. Compared with bamboo-like PSs, lotus root-like PSs are prone to bend during compression. For PSs without connecting plates, a variety of PSs are proposed for each shape. The deformation modes of X, double-headed axe, mixed, two trapezoids, thin waist drum and concave polygon shapes are obtained. Models with greater equivalent densities tend to have better energy absorption efficiency. The compression performance of PSs without connecting plates is significantly better than that of PSs with connecting plates. In addition, a PS made of nylon 11 is manufactured and tested to further verify the performance of PSs. These PSs have uniform structural stiffness, reasonable deformation modes, and efficient energy absorption effects. Their excellent compression properties depend on the gradual collapse of cells.