Crashworthiness And Optimization Design Of Smooth-shell Lattice-filled Tube Under Bending Load

Thin-walled structures are widely used in engineering a pplications.In order to improve the mechanical properties of thin-walled structures,porous structures are usually filled into thin-walled tubes.However,the traditional porous structure has many shortcomings such as randomness,inhomogeneity and anisotr opy.In recent years,a novel biologically inspired porous lattice structure based on triply periodic minimal surface(TPMS)has attracted attention due to its high energy absorption capacity,which provides new ideas for the research of new energy absorbe rs.The crashworthiness of thin-walled tube may be highly improved if it is filled by smooth-shell lattice.However,there are few researches on studying the crashworthiness of the smooth-shell lattice-filled structures.For this reason,our studies take TPMS-filled tube as the research object,and analyzes the crash resistance of the TPMS filled tube under bending load.The bending crashworthiness of the smooth-shell lattice-filled structure is investigated jointly using the method of experiment,numerical simulation and empirical formula fitting in this stu dy.The main research contents of this article mainly include:(1)Three kinds of TPMS lattice structures,Primitive,FRD and Gyroid,were prepared by adding material manufacturing technology,and the me chanical experiments and tensile tests of TPMS-filled tubes and materials were carried out.Corresponding model is established by FE method,and experimental results are compared with simulation,which indicates that FE models can correctly represent the experimental results.A sufficiently accurate finite element model is established in this paper,which can be used for the next parameter study.(2)The effects of design variables and loading conditions on the cr ashworthiness of TPMS-filled tubes are studied.The design variables include: the thickness of the TPMS structure t,number of TPMS cells n,tube thickness b,and side length l of the section;The loading conditions include: impact velocity v,position p,punch angle θ,supporters span S,and punch size R.Meanwhile,the deformation pattern of the TPMS-filled tube under three-point bending and other loading conditions is also analyzed.TPMS-filled tube shows excellent energy absorption advantages at low density in the conparison with foam-filled tube.(3)Multi-objective optimization methods are used to optimize the crashworthiness of TPMS-filled tubes.The PRS metamodel and NSGA-II are employed,while the peak crushing force(PCF)and spe cific energy absorption(SEA)are chosen as the optimization objectives.Thickness of the TPMS shell t and the tube thickness b are selected as variables.The dimensional analysis method is used to predict the bending response of the TPMS filled tube,and the empirical formula of the TPMS-filled tube bending response curve is fitted.The research results show that TPMS-filled tubes have better bending resistance than traditional foam-filled and empty tubes at a same weight.TPMS-filled tube can be used as an excellent energy absorbing device in impact engineering.