细编穿刺C/C复合材料热导率数值模拟

根据细编穿刺复合材料的细观和微观结构,分别建立了纤维束和细编穿刺单胞有限元模型。采用周期性非绝热温度边界条件,计算了纤维束和材料整体的等效热导率。计算结果与经验公式比较,具有高度的一致性。在此基础上,进一步研究了纤维体积分数、基体和纤维热导率对材料热导率的影响。结果表明,随着纤维含量的增加,材料两个方向热导率均有不同程度的下降,且差异逐渐减小,且基体对热导率影响作用较大。文中采用的模型和周期性边界条件与理论预期符合较好,为材料热学和热力耦合问题的分析提供了有用参考。

Simulation on effective thermal conductivity of fine weave pierced C/C composite

Based on the meso and micro structures of the fine weave pierced C/C composite,finite element models of a single braiding yarn and C/C composites were established, respectively.By using the periodic non-adiabatic temperature boundary condi-tion, the effective thermal conductivity of yarns and composites were calculated. The calculation results were highly consistent with empirical formula.Furthermore, the law of effective thermal conductivity by material parameters(i.e.fiber volume fraction,fiber and matrix thermal conductivity) was studied. With the increase of the fiber fraction, the transverse and longitudinal effective thermal conductivities decrease with reduced discrepancy.The thermal conductivity of the matrix has much more effects on the global effec-tive thermal conductivity.Based on the FE model and boundary conditions proposed in this paper,the calculation results are in good agreement with the theory, which provides a useful reference for the analysis of thermal and thermo-mechanical coupling.