The Study On Crashworthiness Of Bionic Microcircular Structure

The thin-walled metal structure is widely used in the design of vehicle front longitudinal rail structure with excellent mechanical properties and light weight,and its crashworthiness can be upgraded by improving the structure.In order to break through the energy absorption bottleneck of traditional thin-walled structures,the application of bionic elements in the design of thin-walled structures has become a research hotspot in recent years.In order to further improve the energy absorption of thin-walled structures and provide reference for the design of vehicle front longitudinal rail,based on the observation of several excellent biological structures,this paper proposes a bionic microcircular structure that can be applied to the design of thinwalled structures.Using the combination of experimental verification,simulation analysis and theoretical derivation,this kind of bionic microcircular structure is deeply studied.The main contents are as follows:(1)Based on the microstructure of the beetle elytron and the cross-sectional structure of the stalk of the horsetail herb,the bionic microcircular structure is proposed and the finite element model of the bionic microcircular structure is established.The quasi-static axial crushing test of the external square tube of the bionic microcircular structure is carried out.The results of the crushing test and the finite element simulation model are compared and analyzed,and the validity of the finite element model of the bionic microcircular structure is verified.(2)Based on the results of crushing test and validated finite element models,the deformation modes of bionic microcircular structures are analyzed.At the same time,the finite element simulation parameterization of traditional rib structure and bionic microcircular structure is studied.The specific energy absorption of the two structural units was compared.The results show that the bionic microcircular structure is better than the traditional rib structure on deformation mode,and the energy absorption efficiency is improved more than 32.20%.(3)Based on the simplified super folding element theory,the theoretical expression of the average crushing force of the bionic microcircular structure under quasi-static loading is derived.This formula indicates that the average crushing force of the bionic microcircular structure is influenced by the plastic flow stress of the material,the wall thickness of the structure,the number of additional panels and the radius of the intermediate cylinder.The theoretical expression is verified by experimental data,which can better predict the mean crushing force of the bionic microcircular structure.(4)Determine the applicable range of the theoretical expression of the average crushing force of the bionic microcircular structure.Change the angle between the additional panel of the bionic microcircular structure and the outer wall of the intermediate cylinder in the same finite element environment to obtain new bionic microcircular structures.The crashworthiness parameters of bionic microcircular structures with different angles are compared.The results show that changing the angle can affect the energy absorption and initial peak force,which provides guidance for the design of the structure of vehicle front longitudinal rail.