Design And Research Of Impact Resistance Of Hybrid Thin-walled Structures With Multiple Geometric Cross Sections

Collision impacts occur in social life all the time,among which harmful collisions seriously threaten people's health and property safety.One of the effective measures to eliminate or mitigate the adverse effects of harmful collisions is to design a protective structure.Thin-walled structure has been widely concerned because of its advantages of light energy absorption and good effect in engineering equipment protection design.At present,thin-walled protective structures are mainly concentrated on single-walled and multi-cell structures with a single geometric cross-section.This paper presents a novel design method of thin-walled protective structures with hybrid multi-geometric cross-sections,focusing on the impact resistance of hybrid thin-walled structures with geometric cross-sections.The main content focuses on the following two aspects:?1?Study on axial impact resistance of thin-walled structures with hybrid cross sections.Firstly,the impact resistance of the hybrid structure is studied by means of experimental test,numerical simulation and theoretical prediction.The theoretical model of the average collision force and energy absorption of the hybrid structure was established using the super folding element theory.The optimization strategy of the multi-agent model and the multi-evolution algorithm was used to carry out multi-objective optimization of the cross-section size of the hybrid structure,and selects the Pareto frontier obtained from optimization based on the normal boundary intersection method.Finally,the comparative analysis of the mechanical properties of the typical single section and the hybrid section protection structure are carried out under the same mass,it is found that the hybrid structure has excellent impact resistance performance,which has a good potential as a protection structure design.?2?Study on the impact resistance of hybrid thin-walled structures at multiple impact angles.To further explore the multi-operating impact performance of the hybrid design protective structure,the paper further proposes and analyzes the impact resistance performance of the structure obtained from the hybrid design of triangular,pentagonal,hexagonal and circular cross-sections under multi-angle impact.It is found that hybrid structure folds stably to dissipate energy and has good impact stability in the small angle load.However,the deformation mode gradually changes to global bending when the impact angle is large.Technique for order preference by similarity to ideal solution was used to classify the mechanical performance of the hybrid structure and found that the SC₂ hybrid structure?a square cross section is placed on the outside and a circular cross section is placed on the inside,and the ribs connected to the internal circular cross section through the ribs at the midpoint of the side length of the square cross section?has the highest comprehensive benefit,that is,SC₂ hybrid structure has the best impact resistance performance under multi-angle impact.Finally,the application of the hybrid structure in the bumper energy absorption system of the vehicle is studied,and it is found that the bumper with the hybrid structure energy absorption box has obvious lightweight effect and impact resistance performance compared with the initial design,which indicates that the hybrid structure has certain potential application in the vehicle.