| In this paper,Carbon Fiber Reinforced Polymer(CFRP)was applied to the design of wheel rim,taking the three-piece wheel of a racing car as the object of this study.This entire process contains the following four parts:structure design of the wheel rim,the optimization of ply percentage,the optimization of ply thickness and the optimization of ply sequence.The following aspects are the main content of this paper:1)Explore the research methods of a CFRP wheel structure.Finite element models under three test conditions according to the automotive wheel test specification were built:the bending fatigue condition,the radial load condition and the impact condition;2)Study on the design method of varying Cross Section Structure of Composite Materials.A partitioned rim structure was obtained on the basis of free size optimization results,taking into account the different requirements of materials and structures in different regions of the rim structure;3)Analyze the sensitivity of the rim structure in the carbon fiber laying directions of[0/45/-45/90].The most sensitive ply direction was set for optimization variable,thus simplifying the optimization variables,and the complex multivariate optimization problem was simplified as a multilevel optimization problem with less variables;4)With the help of ISIGHT integrated optimization platform,the percentages of fiber layer thickness of different rim part were optimized under static conditions;The RBF surrogate model of static and dynamic analysis of wheel structure was constructed,and NSGA-Ⅱ optimization method was used to optimize the thickness of each rim part;5)The fiber laying sequence of the carbon fiber rim structure was optimized by combining the process constraints,and the optimization results of the carbon fiber rim structure were re-interpreted.Besides,the transition layer of the carbon fiber structure was set up to further excavate the structural design potential of the CFRP.This paper sets the CFRP "material-structure" integrated design idea as the starting point.Through the above process,a partitioned multilevel optimization of the reference CFRP wheel rim structure was completed.With the help of the free size optimization method and the sensitivity analysis method,the wheel rim structure was refined and the optimization variables were simplified.At the same time,the surrogate model and the genetic algorithm optimization method were used in the optimization process of the rim partitioned thickness to solve the multiobjective optimization problem.Compared with the initial structure,the spe’cific stiffness(stiffness/mass)of the optimized wheel structure is greatly improved and the mass has changed from the initial 2.74kg to 2.23kg,which is 18.6%lower than that of the initial wheel structure.The performance of the wheel under dynamic and static conditions were all improved.The maximum material strain,which is the key parameters of the fatigue damage under the impact of the rim,has been reduced to a large extent from 1.49E-02 to 6.98E-03,which is reduced by nearly 53%. |
