低密度碳酚醛复合材料微观烧蚀建模及响应预示研究

The macroscopic response of low-density carbon-phenolic composites (PICA) is studied by the multiphysical field coupling calculation combining with the ablation characteristics analysis in the microscale, which are of great significance for manufacturing, structural design and application of the PICA. The thermal pyrolysis characteristic for the PICA are studied to establish the thermal pyrolysis kinetic model. And the thermal protection and insulation mechanisms for the PICA are obtained. The chopped fiber skeleton model can be modelled by the experimental observation and statistical theory. The microscopic ablation and transport characteristic for the PICA can be studied by the direct simulation Monte-Carlo method. And the transport characteristics for the phenolic resin and carbonized matrix could be analyzed by the fractal model. Based on the microscopic model, the mechanical behavior the PICA are investigated, in which the adhesive function of the resin and carbonized matrix and the interaction between two chopped fibers can be simulated by the spring elements. The macroscopic thermal and mechanical response of the PICA can be studied by the multphysical coupling calculation combining the material information obtained by the local volume average from the microscopic model. The aim of the project is to develop micro and macroscopic ablation model for revealing material ablation mechanisms and to establish the thermal and mechanical response analysis method of the PICA under high temperature conditions, which can lay a theoretical foundation for the material design and the structural analysis of the PICA.

从微观尺度分析低密度碳酚醛复合材料（PICA）烧蚀特性，结合多场耦合计算实现对材料宏观响应分析，对PICA材料的研制、结构设计和应用具有重要意义。本项目对PICA材料的热分解特性进行分析，建立材料的热解动力学模型，对材料的防隔热机制进行分析；通过实验观测结合统计理论建立随机短切纤维骨架模型，利用直接Monte-Carlo方法对材料微观烧蚀过程以及传输特性进行模拟，采用分形理论对不同热解程度的酚醛树脂和碳化材料的传输特性进行建模分析；基于微观模型，通过弹簧单元模拟树脂或碳化材料的粘接以及纤维之间的相互作用，对材料的力学行为进行分析；对微观模型进行局部体积平均，通过材料宏观多场耦合计算，对材料宏观热/力响应进行分析，并利用烧蚀和热变形实验进行验证。本项目目的是发展PICA材料微宏观烧蚀模型揭示材料烧蚀机理，建立材料高温条件下力/热响应分析方法，为PICA材料设计和结构分析奠定理论基础。

本项目从微细观角度研究了低密度碳酚醛复合材料（PICA）烧蚀特性及高温力学响应，可进一步指导PICA材料的研制、结构设计和应用。本项目对PICA材料开展了热分解特性进行分析，建立了材料的热解动力学模型，通过对材料高温实验揭示了材料的防隔热机制；通过实验观测结合统计理论建立了随机短切纤维骨架模型，利用格子玻尔兹曼方法研究了材料热传输特性， 通过有限元方法分析了材料的力学性能；建立材料微观烧蚀模型，对材料的微观烧蚀过程进行了分析；对微观模型进行了局部体积平均，通过材料宏观多场耦合计算，对材料宏观热/力响应进行了分析，并利用烧蚀实验进行了验证。本项目发展了PICA材料微宏观烧蚀模型，揭示了材料的微观烧蚀机制，建立了材料高温条件下力/热响应分析方法，为PICA材料设计和结构分析奠定了理论基础。