Reliability Optimization Design Of The Hybrid Structure Anti-intrusion Door Beam

The side pole impact is one of the most common traffic accident patterns.In the side pole impact,the stiffness of the pole is very high,the crash area is relatively concentration and week,and the space of energy absorption is fairly small.For these reasons,the side pole impact usually results in a high casualty rate of the occupants.However,there is a limited concern about the pole side impact in the study of collision accidents at home and abroad.Therefore,it is not only of great practical significance but also difficult to improve the crashworthiness of body structure under the side pole impact.With the aim of addressing the above issues,the anti-intrusion door beam,one of the most important protective components in the side door assembly,was chosen as the research object in this dissertation.A novel hybrid structure with double cylindrical tubes and Terocore foam filler was taken to modify the design of the door beam.Besides,a system optimization method was employed to optimize the structural parameters of the door beam with the hybrid structures.The main research contents of this dissertation were as follows:The finite element model of hybrid structure under the dynamic three point bending was established and verified.Based on the analysis of the simulation results,it was discovered that the outer tube thickness,inner tube diameter and inner tube thickness had effects on the bending performance of hybrid structure.Based on the European New Car Assessment Program(Euro-NCAP)side pole impact test standard(2009 edition),the vehicle finite element model was established and validated by the real test result.From the aspects of the door inner panel's intrusion in the position of the dummy's pelvis,the average impact force of the rigid column interface as well as the mass,the initial hybrid structure design was compared with the original single tube design.The feasibility and superiority of the initial hybrid structure design were preliminarily proved.Optimizations were applied to further improve the crashworthiness of the hybrid structure door beam.In the optimization process,Particle Swarm Optimization(PSO)algorithm was introduced to optimize the hyper parameter of the Kriging(KRG)model.So,the hyper parameter could obtain its optimal value in any initial conditions.Thus,the precision of the model was enhanced.Finally,an example was used to prove that the PSO-KRG model could provide more accurate prediction response than the original KRG model.The optimal results showed that,compared with the original design of single tube,the reliability optimization design of the hybrid structure reduced the quality of the door beam by 13.944%,and the safety performance and reliability were improved under the side pole impact.This design is very practical in the engineering.