Lightweight Research Of Multi-material Front Cabin Structure Based On Crash Safety

With the substantial increase of car ownership,the pressure of energy consumption,environmental protection and driving safety are exerting increasing pressure on the sustainable development of the automotive industry.The research shows that vehicle lightweight is an important measure to achieve energy conservation,emission reduction and improve vehicle power,handling stability and safety.In addition,the multi-material body represents the future development of the body structure,which can reduce the quality of the vehicle on the basis of guaranteeing the performance of the body.The front cabin structure is a complex energy absorption system.In the total energy of the frontal crash of the vehicle,the front cabin components absorb about 80% of the energy.Therefore,in order to improve the safety and lightweight of the vehicle,it is particularly important to optimize the front cabin structure by the method of multi-material lightweight design.In the Dissertation,a pickup truck is selected as the research object,after the frontal crash performance is evaluated,Multi-material matching of front cabin energy absorption systems is achieved by incorporating new materials such as high-strength steel,aluminium alloy and carbon fiber reinforced composites.Combining with the method of multi-objective optimization,the method improves the safety of the vehicle and achieves a significant lightweight effect.The main research work of the Dissertation is as follows:1.The finite element model of vehicle frontal crash is established in the finite element software Hypermesh,and the simulation calculation and analysis are carried out on the Ls-dyna platform.According to the requirement of the regulations GB11551-2003,the safety indexes such as vehicle deformation,B-pillar acceleration and front panel intrusion are analyzed,and the safety performance of vehicle frontal crash is preliminarily evaluated.2.Facing the decision-making problem of material selection,based on the requirement of green design for sustainable development,closely adhering to the two research objectives of safety and lightweight in this Dissertation,the improved TOPSIS multi-attribute decision-making method is used to systematically select lightweight materials,and the alternative materials for front cabin structure are obtained.3.The energy-absorbing structure of the front cabin is divided into primary and secondary energy-absorbing parts,which respectively match the lightweight materials decided in the previous step.The primary energy-absorbing parts are matched with multi-material by the method of experimental design.On this basis,the secondary energy-absorbing parts are matched with carbon fiber composites,and the impact safety and lightweight effect of the multi-material front cabin structure are verified step by step.4.RBF approximation model is established in Isight platform,and NSGA-II algorithm is used for multi-objective optimization of primary energy-absorbing parts in the front cabin.Finally,by using the lightweight method of multi-material matching and multi-objective optimization,the quality of energy absorbing components of the front cabin is reduced by 48.54 Kg,and the weight is reduced by 51.67%,the weight reduction effect is remarkable,and the safety performance of frontal crash is greatly improved.