Reliability Optimization Design Of Plain Weave Composite Pure Electric Vehicle Battery Box

Under the multiple pressures of the traditional energy crisis,environmental pollution and the concept of energy saving and emission reduction,pure electric vehicles have emerged and achieved a booming development.However,their poor range and low safety performance have also become issues that need to be addressed by the entire new energy vehicle industry.Research has shown that the range and safety performance of pure electric vehicles are inextricably linked to their own mass,and the battery box,as the heaviest structure of the entire electric system apart from the battery pack,is of great significance for its lightweight design.At the same time,the application of carbon fibre composites to the lightweight design of battery boxes has also become a focus of research.Compared to traditional unidirectional composites,woven carbon fibre composites have more uniform mechanical properties,more mature manufacturing processes and a wider design range than traditional unidirectional composites.Therefore,this paper takes the plain woven carbon fibre composite battery box as the research object,takes lightweight as the research objective,replaces the metal material of the original battery box with plain woven composite material through equivalent design idea,and optimizes the design of the woven composite battery box by using Kriging model and reliability theory.The research in this paper is as follows.Firstly,this paper proposes a prediction method for the elastic properties of plain woven composites from the fine structure of woven composites,combining periodic boundary conditions and homogenization theory,and compares the predicted values with the experimental values to verify the validity of the method.Based on the prediction model,the influence of the geometrical parameters of the fine structure on the mechanical properties of the composite is investigated in depth,laying the theoretical and data foundation for the subsequent optimization of the design of the battery box and the analysis of uncertainty factors.Secondly,this paper establishes finite element models for metal and woven composite battery boxes respectively based on the principle of iso-generational design.The static analysis conditions,modal analysis conditions and dynamic extrusion conditions are developed according to the national standard and enterprise requirements,and the performance response values of the two different materials are compared and analyzed under the same conditions.The results show that while the plain woven composite battery box has a good weight reduction effect,the performance parameters are still better than those of the metal battery box.The results indicate that plain woven composites are valuable in the lightweight design of battery boxes.Finally,this paper comprehensively considers the influence of fine structure geometry parameters on the elastic properties of woven composites under uncertainty factors,uses DOE experimental design to perform sensitivity analysis on the parameters,and selects the parameters with larger sensitivity values and macroscopic layup parameters as the optimized design variables according to the experimental results.The test samples are generated by the Latin superlift method,and the Hyper Mesh-ABAQUS software is used to jointly simulate different finite element models of the battery box,and the samples and their performance response values are used to establish the Kriging model.Then the optimized design model is established with the minimum total mass of the plain woven composite battery box as the optimization objective and the stiffness performance and modal frequency of the original battery box as the boundary conditions.At the same time,considering the objective function,constraints and many uncertainties in the design variables in the optimization model,this paper adopts the sequence optimization and reliability assessment method to optimize the reliability design under different reliability indexes,and verifies the reliability of the optimal solution obtained from the optimization in conjunction with the Monte Carlo simulation method.The research of this paper can provide a reference method for the effectiveness and reliability of lightweight design of plain woven composite battery box under the non-deterministic condition of material variables.