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碳-碳复合材料应用于热结构,需要了解控制性能的微观结构特性。本文目的是验明有关碳-碳复合材料破坏的微观结构因素,并在发展复合材料拉伸特性的分析模型中应用这些数据。试验方法是:用扫描电子显微镜在载荷下观察单向和多向复合材料中裂纹的起始和扩展。裂纹扩展的研究表明:裂纹通道是受基质中高度定向层面所控制;断裂不是发生在纤维-基质的界面处,而是发生在基质中。只有当假设纤维是弯曲的且被扭缠基质包皮所包围时,此分析模型能成功地预测应力-应变曲线。
Carbon-carbon composites used in thermal structures require understanding of the microstructural properties of the control properties. The purpose of this paper is to identify microstructural factors related to the failure of carbon-carbon composites and to apply these data in developing analytical models of the tensile properties of composites. The test method was to observe the onset and propagation of cracks in unidirectional and multidirectional composites under a load using a scanning electron microscope. Crack propagation studies show that crack channels are controlled by highly oriented layers in the matrix; fractures do not occur at the fiber-matrix interface but rather in the matrix. This analytical model can successfully predict the stress-strain curve only if the fiber is assumed to be curved and surrounded by a twisted mantle.