Crashworthiness And Optimization Of Horsetailbionic Thin-walled Structures

With the advancement of science and technology,more and more structural equipment has put forward higher requirements for lightweight and high-strength materials,and thin-walled structures have achieved considerable results after systematic optimization and design by engineers.This paper uses ABAQUS finite element software to analyze the crashworthiness performance of two species of Equisetum biomimetic thin-walled structures(HBTS and VHTS)under lateral impact.The optimization design method optimizes the two structures,and obtains the Pareto frontier of specific energy absorption and maximum peak load,and studies the design parameter distribution of each structure on the frontier.It provides a certain reference value for engineering designers in the design optimization of thin-walled structures.(1)The finite element model of HBTS under lateral impact load was established by ABAQUS finite element analysis software and its accuracy was verified.The effects of overall wall thickness,inner diameter and number of ribs on the crashworthiness and deformation modes of HBTS were analyzed.After sorting and analyzing the data,it is found that the inner diameter,the overall wall thickness t and the number of ribs have a significant impact on the crashworthiness of the structure.Specific energy absorption and maximum peak load increase with the number of ribs and the overall wall thickness of the structure.When t is large,an appropriate increase in the inner diameter can improve safety performance without reducing the specific energy absorption of the structure.Crash force efficiency is insensitive to changes in overall wall thickness,number of ribs,and inner diameter.Through the comparison and research of two different quality HBTS,it is found that the wall thickness change of each part of the HBTS will significantly affect its deformation mode and then affect the energy absorption,specific energy absorption and maximum peak load.Therefore,it is necessary to optimize the wall thickness of each part of the HBTS.The optimization was carried out using the optimization design method based on ABAQUS and mode FRONTIER.The full factorial experimental design method was used to generate 3750 groups of real points in the design space and perform numerical calculation.The surrogate models of specific energy absorption and maximum peak load are constructed from3750 real points,and the results show that the kriging surrogate model has the highest accuracy.The Kriging surrogate model is combined with the multi-objective particle swarm optimization algorithm to carry out multi-objective optimization.After optimizing the five design parameters of the HBTS,the Pareto frontier is obtained,and the distribution of the design parameters of each HBTS on the frontier is analyzed.The accuracy of this front is verified by finite element simulation.In the optimized Pareto front,HBTS with 14 or 16 ribs occupies the vast majority,and HBTS with other ribs only appears when the maximum peak load is small.The Pareto frontier obtained by the optimization is verified,and the peak load is limited to 5k N and10 k N,compared with the numerical simulation results,the errors of specific energy absorption and maximum peak load predicted by the kriging surrogate model are all in 2.73% or less.(2)Equisetum is widely distributed in Europe,North America,Russia,Japan and other parts of the world,and has excellent environmental adaptability.According to the structural characteristics of its V-shaped connecting rib,which is different from other equisetum plants,5kinds of structures with different mumbers of ribs are designed.In order to improve the crashworthiness of such thin-walled structures under lateral impact,numerical models was established and analyzed using ABAQUS.The results show that VHTS with 2 and 3 ribs has larger peak load and smaller specific energy absorption than VHTS with other ribs in the same mass of VHTS structure,which should be avoided in crashworthiness design.this structure.The VHTS structure was optimized using the optimization design method based on ABAQUS and mode FRONTIER.The full factorial design method was used to generate 3125 groups of real points in the design space,and a surrogate model was constructed after numerical calculation.Kriging surrogate models and radial basis functions have higher accuracy than quadratic,cubic,and quartic polynomial response surfaces.The maximum peak load is limited to 45 k N,and the Pareto fronts obtained by different surrogate models are verified.The results show that the kriging surrogate model has the best prediction effect,and the errors of maximum peak load and specific energy absorption at the predicted point are 0.68% and 0.83%.