复合材料由于其微观结构的非均匀性以及复杂的力学特性,使得其零部件设计难度大大增加。采用多尺度分析的方法,根据T300/Epoxy斜纹机织复合材料细观几何参数,建立其单胞几何模型,引入周期性边界条件对单胞结构进行有限元分析,进而预测复合材料层合板三维弹性性能参数,并通过力学试验证明试验结果和预测结果较为接近;利用LS-Dyna中的MAT_54建立复合材料渐进失效模型,通过三点弯曲试验结果调整模型参数,最终得到的复合材料渐进失效模型仿真结果与试验结果一致;将调整好的复合材料渐进失效模型应用到电动车复合材料车身骨架轻量化设计中,对复合材料骨架进行顶压仿真以及柱碰仿真分析。分析结果表明,复合材料车身骨架设计符合法规要求,与铝合金骨架相比,在重量减轻59%的同时表现出更好的耐撞性能。
Design of composite structure appears more challenging compared with metallic counterparts because of its microstructural heterogeneity and sophisticated mechanical property. The crashworthiness of composite body structure is investigated by using multiscale approach. The representative volume elementis established by geometric parameters which are obtained by measuring the microscopic structure of T300/Epoxy. Coupled with the periodical boundary condition, the representative volume element is adopted to predict the 3D elastic properties of laminate composite by the finite element method. And the prediction results coincide with the experimental data well. A progressive failure model of laminate composite is established by using material model MAT_54 of LS-Dyna. The simulation results of three points bending test are in good agreement with experimental results by adjusting the model parameters according to experiment results. This model is applied to crashworthiness analysis of composite body structure for electrical vehicle under the roof crash and side pole impact. The simulation results indicate that the design of composite body structure meets the requirements. Meanwhile, the crashworthiness of body structure has been increased coupled with a 59% saving in the body weight compared to the aluminum body structure.
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