Study On Axial Compression And Impact Mechanical Properties Of Multicellular Honeycomb Tube Structures

Thin-walled tube structures have been widely noticed in recent years in engineering fields such as automobiles,high-speed trains and aircraft because of their advantages of light weight,high strength and high energy absorption.The energy absorption of thin-walled tube structures is significantly linked to factors such as structural style and loading pattern.Therefore,this paper is based on three pore types,hexagonal,re-entrant and square,different styles of new thin-walled tube structures are designed by changing the pore types and structural twist angles.The mechanical properties of thin-walled tubes were investigated using experiments and finite element simulations to obtain the deformation modes and energy absorption of thin-walled tube structures under various loading methods.The main contents include:(1)The effects of increasing webs on the deformation mode and energy absorption of multi-cell thin-walled tube structures are investigated by experiments and simulations.The results show that adding different forms of webs can effectively enhance the energy absorption of the structure for hexagonal and re-entrant pore types,respectively.When compressing at low-velocity under the condition of ensuring consistent quality,the energy absorption of hexagonal thin-walled tube is weakened after adding webs,and the energy absorption of re-entrant thin-walled tube is enhanced,and the energy absorption of square thin-walled tube changes with the way of adding webs.The impact effect on the energy absorption of the hexagonal thin-walled tube with added webs is small,while the energy absorption of the other two pore types with added webs shows a pattern similar to that of low-velocity compression.(2)The twisting feature is introduced into the single-cell thin-walled tube,and the new single-cell thin-walled tube is formed by twisting angle based on three pore types.And combined with the multi-cell thin-walled tube studied in the previous section,the new singlecell thin-walled tube is formed by removing the web.Quasi-static compression experiments and finite element simulations were performed on single-cell thin-walled tubes,and the effects of changing the pore type,twist angle and compression velocity on their deformation modes and critical loads were investigated.The results show that the single-cell thin-walled tube formed by removing the web of the multi-cell thin-walled tube can effectively increase the critical load.Under quasi-static compression,although the twist angle decreases the critical load of the thin-walled tube,the critical load of the hexagonal thin-walled tube increases with the increase of the twist angle after twisting.Under impact,single-cell thinwalled tubes usually form folding units,and the higher the impact velocity of the same configuration the more folding units are formed,and these are playing an important role in the energy absorption of the structure.Thin-walled tubes with a certain twist angle show a better energy absorption capacity under impact.(3)Based on the results of the study on the mechanical properties of single-cell thinwalled tubes at twist angle,the twisting features are introduced into the multi-cell thinwalled tubes to investigate the deformation mode and energy absorption of the multi-cell thin-walled tubes after twisting.The results show that the twist angle and compression velocity have significant effects on the compression properties of twisted thin-walled tubes.When the twist angle exists,the instability direction of the thin-walled tube structure will change with the twist angle,and the instability usually occurs at the position of the angle between the top symmetry axis and the bottom symmetry axis.Under quasi-static compression conditions,the SEA is maximum at a twist angle of 30° for the hexagonal pore type,0° for the re-entrant pore type,and 60° for the square pore type.When subjected to impact loading,the force-displacement curves of the three pore types are similar.The higher the impact velocity,the more obvious the influence of the overlapping region of the twisted thin-walled tube and the more stable the deformation process of the structure.Due to the influence of the overlapping region,the SEA of the twisted thin-walled tube decreases with the increase of the twist angle.