碳布叠层穿刺复合材料多尺度传热特性研究

为了深入认识复合材料的多尺度传热特性,预测复合材料宏观热物性参数,基于通用单胞思想和多尺度传热特性分析,建立了一种有效预测碳布叠层穿刺复合材料等效热物性参数的方法。基于电镜扫描分析了纤维束和编织结构的特征,采用通用单胞思想,建立了介/细观传热分析模型,通过数值仿真进行了一系列的多尺度传热特性分析,譬如:纤维体积分数对纤维束结构传热特性的影响、穿刺纤维束大小对编织结构传热特性的影响分析,在此基础上,建立了胞体模板扩展,初步将介/细观结构研究规律应用到宏观结构热物性预测,并进行多层胞体传热特性分析。验证实验表明:等效热物性预测值与实验值吻合较好,方法有效,为深入理解认识碳布叠层穿刺复合材料的介/细观传热特性提供了有效的分析手段。

Multiscale heat transfer analysis of Z-directional carbon fiber reinforced braided composites

In order to study multiscale heat transfer characteristics of the Z-directional carbon fiber reinforced braided composites, a procedure for predicting equivalent thermal property parameter through a combined approach of the generalized method of cells and multiscale heat transfer analysis is presented. With multiscale structure investigation by scanning electron microscopy, the generalized method of cells is adopted to establish micro-structure model of yarn and meso-structure model of composites for heat analysis. In the sequel, a three-dimensional numerical calculation method for heat-transfer in complex structure is developed using hybrid grid. Based on this, the laws of thermal property influenced by material parameters (i.e., fiber volume fraction in yarn, as well as the size of Z-puncture fiber) are studied by numerical simulations of heat transfer at different length-scale with consideration of isotropy and anisotropy property of component materials. Meanwhile, with adoption of multi-layers cells model, the global equivalent thermal property parameters, such as equivalent conductivity coefficient, equivalent density as well as equivalent specific heat, are predicted for the period of structure in composites considered fully. Finally, validation experiment is made. It is verified that the equivalent thermal parameter predicted by this method agrees well with the experimental values. The results demonstrate that the method presented in this work is a promising means for investigating micro-structure/meso-structure heat transfer characteristic of composites.