Optimization And Research Of Composite/Metal Door Beam Based On Side Impact

With the growth of automobile sales and ownership in China,the problems of energy,environment and automobile traffic safety are becoming more and more serious.Therefore,the automobile industry puts forward higher requirements for the safety and energy consumption rate of the automobile.The vehicle lightweight and the use of new energy are important ways to improve the current problems.In recent years,the application of lightweight materials such as carbon fiber composite?CFRP?has become the development trend of automobile lightweight.As one of the most important protective parts to protect the passengers,it is of great significance to explore the application of composite/metal composite structure in vehicle door anti-collision beam.Composite/Metal hybrid structures,which not only combine high-strength with low-density composites but also with low-cost and easy-manufacture metallic materials,exhibit considerable potential to provide cost-effective energy-absorbing devices for automotive applications.Based on the finite element simulation method of side impact and the test of composite/metal composite structure foundation sample,the lightweight of the hybrid structure of door crash beam is studied.The main research contents are as follows:In the first part,based on the side collision law of FMVSS 214,the simulation model of door side column collision including anti-collision beam was established,and bearing capacity and energy absorption of the door anti-collision beam were analyzed.The crashworthiness resistance of the door anti-collision beam with different geometric structures was compared.The results showed that the anti-collision beam of the hut structure had excellent performance and high design ability.Then,the optimization design of the cap type anti-collision beam is carried out.Taking the peak load(F_max)and the energy absorption?EA?as the objectives,the BP neural network model and the multi-objective genetic algorithm?NSGA-II?were combined to obtain the optimal external dimensions of the hut type anti-collision beam,which are a=16 mm,b=38 mm,c=17 mm and?=95°,and provide the geometric dimensions for the door CFRP/metal hybrid beam.In the second part,a reliable finite element model of composite/metal hybrid structure was established by the experiment of CFRP/Al hybrid tube under transverse loading.Firstly,the basic properties of materials were obtained by materials test standard.Secondly,the accuracy of the double shell and continuous shell finite element model of CFRP/Al hybrid tube under transverse load was compared.The research showed that the modeling method of continuous shell was more accurate,and the error was less than 5%.It can be used for finite element modeling of CFRP/metal hybrid thin-wall structure,which provided a basis for the modeling of door CFRP/metal hybrid beam.The third part was based on the principle of equal stiffness replacement,the simulation model of door CFRP/Al hybrid beam was established and compared with the original steel hut beam.Its specific energy absorption was 0.92 times higher than the original beam,and its mass was reduced by 44.2%.According to the design ability of CFRP,the influences of the thickness,the angle and the sequence of it on the impact resistance of the hybrid beam were discussed.Under the requirement of ensuring the anti-collision performance,with the lowest quality as the target,the three-step optimization method,the layer structure of CFRP/Al hybrid anti-collision beam was optimized.The final mass was 0.853 kg,which is 9.3%lower than that before optimization.Then the best optimal stack sequence was[45/-45/0/0/45/-45/0/0/0/45/-45/0/0/0/45/-45/90/90],where the thickness of single layer was 0.1 mm.Finally,the impact results of CFRP/Al hybrid anti-collision beam before and after optimization under different impact conditions were analyzed.Under the column impact condition,the load-bearing capacity of the optimized CFRP/Al hybrid door beam was increased by 7%and the specific energy absorption was increased by 23%;under the moving deformable barrier impact condition,the optimized hybrid beam reduced the maximum intrusion and the peak intrusion speed of the door inner plate,and effectively improved the crashworthiness of the door...