Crashworthiness Analysis And Optimization Design Of Telescopic High-strength Steel Thin-walled Circular Tubes

With the continuous occurrence of collision,explosion events and a large number of application requirements in various engineering fields,energy-absorbing elements are the main energy-consuming component in the buffer device,which determines the casualties of the personnel and structural damage to a certain extent.In addition,metal thin-walled tubes have the characteristics of light weight,high strength and energy absorption efficiency,so they are widely used in collision energy-consuming systems.Therefore,designing new configurations of metal thin-walled tubes to improve their crashworthiness has become a hot research topic.Based on the research of existing high-strength steel thin-walled tubes,this paper proposed a new type of energyabsorbing element by designing corrugated induced grooves and used LS-DYNA to establish the finite element model.At the same time,this paper studied its crashworthiness under axial impact loads and the geometric parameters of the new energy-absorbing element were optimized for crashworthiness by combining the approximate model and optimization algorithm,which provided a certain reference for future applications in the field of engineering.The main contents are as follows:(1)In this paper,LS-DYNA is used to establish finite element models of highstrength steel thin-walled circular tubes,and their calculated values are compared with experimental values to prove the correctness of the material constitutive model.(2)A new type of energy-absorbing element,namely end telescopic thin-walled circular tube,is formed by setting a corrugated induced groove at the upper end of the high-strength steel thin-walled circular tube,and is established the finite element model.Then,the numerical calculation results are used to analyze deformation modes and energy absorption characteristics of the novel thin-walled tube under different geometric parameters.The results show that under the action of axial impact load,the end telescopic thin-walled circular tubes have three crushing modes: ring mode,mixed mode,and bottom deformation mode,and its geometric parameters have a significant impact on its various crashworthiness evaluation indicators.When the geometric parameters are designed reasonably,the end telescopic thin-walled circular tubes have a better crashworthiness than the ordinary thin-walled circular tubes.Finally,the crashworthiness of end telescopic thin-walled circular tubes is optimized.The Kriging method is used to construct the approximate model response surface and then combines with the NSGA-II algorithm to solve the multi-objective optimization problem,so as to obtain the Pareto frontier diagram.It provides preliminary data and analysis results for the optimized design of crashworthiness.(3)Another new type of thin-walled component,namely middle telescopic thinwalled circular tube,is formed by setting a corrugated induced groove in the middle of the high-strength steel thin-walled circular tube,and is established the finite element model.Then,according to the numerical calculation results,the impact of the middle telescopic thin-walled circular tubes on the crashworthiness of different corrugated induced groove radii and the length of the central thin-walled circular tubes are analyzed.The results show that compared with ordinary thin-walled circular tubes,middle telescopic thin-walled circular tubes can ensure that the maximum peak crushing force greatly reduces without reducing the energy absorption.Finally,with geometric parameters of the novel thin-walled tubes as dynamic variables,the maximum peak crushing force and specific energy absorption as the objective function,the Kriging method and the NSGA-II are used to deal with the problem.Moreover,optimization results are compared with the numerical simulation results,verifying the reliability of the optimization results.