斜纹机织碳纤维/环氧树脂复合材料性能及其在电动汽车轻量化设计中的应用

采用均质法和单胞有限元法, 研究了斜纹机织碳纤维/环氧树脂复合材料的三维本构模型, 并应用于轻量化电动汽车结构的设计计算中。通过光学显微镜观测获得T300碳纤维/环氧树脂复合材料层合板细观结构几何参数, 依据参数建立了代表体积元的几何模型; 结合有限元分析方法与层合板理论对代表体积元模型进行受力分析, 获得了复合材料三维本构模型参数, 并运用单向拉伸与三点弯曲物理试验对所建立的本构模型进行了验证; 通过二次开发, 把该三维本构模型用于轻量化电动汽车结构件的设计中, 并根据汽车安全测试标准对所设计的结构进行了强度校核。研究表明: 运用所建立的三维材料本构模型进行的仿真实验结果与真实拉伸和弯曲试验结果相吻合, 误差分别为4.04%和7.79%, 可用于轻量化结构的设计; 研究开发的电动汽车, 轻量化效果明显, 在满足车身强度要求下整车质量减轻了12%。 

Properties of twill-weave carbon fabric/epoxy composites and its application on light-weight design for electric vehicles

Using homogenization and unit cell finite element method (FEM), 3D material constitutive model of twill-weave carbon fabric/epoxy composites was studied and applied on the light-weight structure of electric vehicles (EV). The micro-geometric structure parameters were obtained by observing the internal microstructure of twill-weave T300 carbon fabric/epoxy composites with the help of optical microscope, then the geometric and FEM of representative volume element of composites laminate were established; The material parameters of 3D material constitutive model was studied using the cell FEM based on the laminate theory, and the predicted values were compared with uniaxial tension and three point bending test values. Through the second development, the 3D material parameters were used on the light-weight electric vehicle structure design, the EV safety was inspected according to federal motor vehicle safety standard (FMVSS571.216). The result indicates that 3D material constitutive model developed is in agreement with tension and bending experiment results, whose relative errors are 4.04% and 7.79%. The weight of EV developed by using the twill-weave carbon fabric/epoxy composites is 12% lighter than that of the traditional vehicle under the same safety condition.