Investigation On Energy Absorption Performance Of 3D-Printed Helical Honeycomb Structure

Due to its excellent energy absorption properties,high specific strength and stiffness,and outstanding design flexibility,honeycomb structures have been widely used in various engineering fields such as impact buffering and energy absorption structures.In addition,in order to improve the mechanical properties of conventional honeycombs,many researchers have developed honeycomb structures with excellent mechanical properties through multi-level design,gradient density design,and bio-inspired design.Bio-inspired design is considered a simple and effective strategy to improve the mechanical and energy-absorbing properties of honeycomb materials.However,the traditional preparation process is difficult to prepare honeycomb materials with novel shapes,such as multi-level honeycombs with triangular lattices,gradient honeycombs with gradient densities,and helical honeycombs with helical shapes.Therefore,the research results on the design,preparation and testing of novel honeycomb structures are lacking.Recently,the rapid development of additive manufacturing technology has made it possible to prepare heterogeneous honeycomb structures.The design and fabrication of novel honeycomb structures are no longer restricted.In this study,based on the regular honeycomb(RH)and the regular square honeycomb,the double-layer helical honeycomb(DLHH)and the multi-layer helical square honeycomb(HLSH)are designed by using the bionic design method.The honeycomb samples with different relative densities were prepared by 3D printing technology,and the mechanical properties of the helical honeycomb were tested by quasi-static compression.The deformation mechanism and theoretical model of the novel helical honeycomb structure were analyzed by finite element simulation,thus revealing the energy absorption regulation mechanism of the helical honeycomb proposed in this study.The double-layer helical honeycombs(DLHH)exhibit a layer-by-layer collapse deformation mode under quasi-static compression.During the compression,the double-layer helical honeycombs(DLHH)show unique double elastic mechanical response regions.The simulation results reveal that the plastic buckling of the cell wall dominates the deformation of the double-layer helical honeycomb.With different relative densities,the mechanical and energy-absorbing properties of the double-layer helical honeycomb(DLHH)are better than those of the regular honeycomb(RH).Finally,the theoretical prediction models of mechanical properties of the regular honeycomb(RH)and double-layer helical honeycomb(DLHH)were obtained through power law fitting derivation.The multi-layer helical square honeycomb(HLSH)exhibits excellent mechanical and energy-absorbing properties under quasi-static compression.At low relative density,the mechanical properties of a multi-layer helical square honeycomb(HLSH)are better than those of a regular square honeycomb(RESH).The plateau stress and energy absorption properties of the multi-layer helical honeycomb(HLSH)are better than those of the regular square honeycomb(RESH)at all relative densities.As the number of helical layers increases,the mechanical and energy-absorbing properties of the multi-layer helical honeycomb structure increase gradually.The finite element simulation results show that the plastic buckling of the cell wall dominates the deformation of the multi-layer helical square honeycomb(HLSH),and more unit cells participate in the deformation during the compression process,so it has higher plateau stress and energy absorption performance.