Multi-objective Optimization Of Car Body Ply In Lattice Core Racing Monocoque

The Formula Society of Automotive Engineers competition,also called the Formula Student Racing Competition,is organized by the Association of Automotive Engineers in various countries,and is participated by undergraduates and postgraduates.The rules of the competition are relatively open.The purpose is to encourage participant to come up with more new and original designs.The HRT racing team of Harbin Institute of Technology at Weihai has maintained a good performance in this competition.The racing’s body of HRT adopts a kind of composite shell structure,which is called Monocoque.This kind of body structure provides superior lightweight properties and strength characteristics.However,the design method of the monocoque racing body has been carried out in a process of “hypothesis-analysis-modification-comparison-redesign”,which is low-efficiency and inflexibale.In addition,there has been no innovation in the laminate core material of the racing body,and traditional aluminum honeycombs and foams have been used without changes.This article takes the HRT-17 C monoque as the research object,and hopes to propose a new type of core material,which is finally applied to use of the monocoque through pre-optimization and later design of the working conditions.In addition,this article hopes to innovate the existing monocoque design method and propose a new forward design method aiming at the characteristics of FSAE,to improve the efficiency of design progress.The main research contents of this article are as follows:(1)Introduction a method of processing and optimizing design of latticestructure core material.The mathematical model of the macroscopic performance of the target lattice is given.The optimization of the meso-structure of the singleobjective and multi-objective is achieved by the mathematical method.It is verified through experiments,and the optimized lattice-structure core material will be used in the monocoque.(2)Simulation analysis of multiple cases of racing monocoque.Based on the characteristics of FSAE competition and the design direction of this article,the finite element simulation models of torsion,bending,8-character surround,braking,launch,and free modal is established respectively.The stress concentration,strain,free mode,torsional stiffness,bending stiffness are analyzed as response we pay attention to.(3)A multi-objective monocoque ply optimization method based on parametric simulation model and fitting response model is introduced.Based on the above simulation model,seven target response approximation models are fitted through sample points from DOE to obtain an integrated multidisciplinary optimization model.The weighted multi-objective method and the multi-objective genetic algorithm are used for optimization.The actual Pareto non-inferior solution is considered and choosen.The effectiveness of optimization model is proved by comparing the responses before and after optimization.