Study On The Design And Crashworthiness Of The Tapered Tube Based On Yak Horn Structure

The thin-walled energy-absorbing structure is widely used in automobile,ship,aerospace and other industrial fields,and is the main component for dissipating impact kinetic energy and buffering energy absorption during collisions.But in the design process,it faces the contradiction of light weight and high energy absorption.Therefore,designing and optimizing the light-weight and crash-resistant thin-wall energy-absorbing structure has aroused extensive attention from scholars at home and abroad.Based on the engineering bionics principle and similarity theory,the research optimizes and improves the traditional thin-wall energy-absorbing structure,and combines bionics with structural crashworthiness design to improve the crash-absorbing energy efficiency of the energy-absorbing structure.The study selected the light-weight tubular filling material yak horn with excellent crashworthiness in the nature as a biological prototype.The results of the full-angle load-bearing test show that the maximum bearing capacity of the yak horn is 11.8 kN and can withstand 3 to 5 full-angle quasi-static compression tests.The quasi-static compression and drop-weight dynamic impact tests were carried out on the yak horn section samples.The results showed that the total energy absorption of the bottom,middle and top samples were 3.04 kJ,1.52 kJ and 0.8 kJ,respectively,and the ultimate strength was 76.97 MPa,65.73 MPa and 56.02 MPa,the compression performance and energy absorption efficiency show a gradient characteristic that gradually decreases from the top to the bottom.The yak horn failure mode presents a deformation mode that gradually buckles from top to bottom.The macro structure analysis of the yak horn shows that the yak horn is a tapered tubular filling structure,which is mainly composed of two parts of the horny shell and the bone core.And,the wall thickness of the horny shell does not change from the bottom to the top in an equal amount,and has a certain gradient change characteristic.The stacked microstructure of yak keratin keratin layer distribution significantly improves the energy absorption efficiency and crash resistance.Based on the analysis of the similarity between the yak horn and the tapered energy-absorbing tube,a bionic tapered tube composed of a tapered shell with variable wall thickness and aluminum foam was designed according to the intensity gradient of the yak horn and the heterogeneous horny shell structure.The finite element analysis models of four thin-walled structures of bionic tapered tube,round tube,square tube and ordinary tapered tube were established,and the axial load compression simulation analysis of the thin-walled structure was completed.During axial compression,the biomimetic conical tube exhibits a stable collapse deformation mode that collapses from top to bottom step by step.The initial peak load of the bionic tube is 51.3 kN,which is 22.4% and 10.1% lower than that of the square tube and tapered tube respectively,and the specific energy absorption is 50.6 kJ / kg,which is 1.24 higher than that of the square tube,tapered tube and round tube,0.9 and 1 times.Processing and preparing two sets of bionic tapered tubes and two sets of tapered tubes filled with aluminum foam structure to complete the quasi-static compression and dynamic impact tests on thin-walled structures.The tapered shell with variable wall thickness from top to bottom can effectively reduce the initial peak load and can significantly increase the specific energy absorption.It is an excellent energy absorption structure with high impact efficiency.Under the premise of ensuring light weight,improve the energy-absorbing impact resistance of the traditional energy-absorbing structure.