Crashworthiness Research And Optimization Design Of Combined Energy Absorbing Structure

The metal thin-walled structure has the characteristics of strong axial impact resistance and excellent bearing performance.When subjected to axial load shocks,the metal thin-walled structure can absorb the kinetic energy of the impact load by stable axial crushing deformation.At present,crushing type energy absorption structure mainly includes planning type,folding type,shrink type,bulging type.According to the different deformation modes,a composite thin-wall energy absorbing structure is proposed to study the deformation mode and crashworthiness under dynamic axial impact load.The following research work has been carried out:(1)Inspired by the TRB technique,the idea of variable thickness is applied to thin-walled aluminum alloy tubes.Through the extrusion to get different sizes of thin-walled tube that is functionally gradient tube.The experimental study on axial crushing of functionally graded circular tubes with different wall thicknesses was carried out,and the crashworthiness was analyzed.At the same time,the crashworthiness characteristics of the functionally graded tube are analyzed by computer simulation.(2)According to different deformation modes of thin wall energy absorbing structure,a combined thin wall energy absorbing structure is proposed.The structure mainly consists of inner tube,outer tube and punch.When the axial load is applied,the combined energy absorbing mechanism absorbs energy through the bulging of the outer tube,the folding energy absorption of the inner tube and the heat absorption between the punch and the inner and outer tube.The energy absorption structure can effectively improve the structure of the total energy absorption and energy absorption efficiency.(3)The finite element model of the combined energy absorbing structure is established,and the reliability of the finite element model is verified by experiments.By analyzing the crashworthiness of the uniform tube structure with the same energy loading structure under the same loading conditions,it is found that the combined energy absorption structure is similar to the uniform energy ratio and the average force of the uniform structure Have a greater advantage.The effects of the structural geometrical parameters on the crashworthiness of the composite energy absorbing structure are investigated.The wall thickness of the inner tube,the wall thickness of the outer tube and the bulging ratio of the outer tube are analyzed,which has a great impact on the crashworthiness of the combined energy absorbing structure.(4)In order to find the optimal energy absorption structure with optimal crashworthiness,multi-objective crashworthiness optimization is carried out.The RBF approximation model is constructed by using the objective function and constraint condition of the crashworthiness optimization problem of composite energy absorption structure.