热防护系统超高温多孔隔热复合材料的设计、构筑及高温损伤机理

Ultra high temperature porous thermal insulation material is one of the key techniques to develop Thermal Protection System (TPS) for high-performance hypersonic vehicles. The quest for more-efficient thermal protection system technologies necessitates the development of lightweight, high-performance porous thermal insulation materials with exceptional temperature toleration and insulation. Unfortunately, these two properties tend to be mutually exclusive. In order to solve this problem, we propose a new method for preparing the thermal insulation materials with micro/nano composite structure by impregnating Al2O3·SiO2 aerogel into porous zirconia fiber skeleton. In this study, based on the viewpoint of integrated high temperature mechanics and heat transfer theory, we would investigate the optimization design of multi-objective, which could guide the preparation of micro/nano composite structure of ultra high temperature porous thermal insulation material. Moreover, we would develop the performance test, characterization method and performance matching of the porous materials. On the one hand, it provides theoretical analysis basis for high-temperature thermal-stress response and failure mechanism of the porous materials; on the other hand, it could provide a precise guidance on performance optimization, rational utilization, and life evaluation for porous materials. The study on ultra high temperature porous thermal insulation material with micro/nano composite structure is becoming a frontier field of solid mechanics. Results showed here enrich and develop the basic mechanisms of strengthening and toughening design for porous material, and afford reliable foundation for this kind of porous material to be used in various thermal protection systems for hypersonic flight vehicles.

超高温多孔隔热材料是新型高超声速飞行器热防护系统研制成败最为关键的技术之一。本项目针对现有隔热材料与结构的耐温性和隔热性能不能兼顾的矛盾，创新地提出Al2O3·SiO2气凝胶浸渗多孔氧化锆纤维骨架的力学设计方法与制备工艺方法，构筑新型微/纳孔复合结构来实现多孔隔热材料的耐温性、力学和隔热性能的协同提高。本项目拟将传热学与高温力学相结合，发展多目标的材料微结构优化设计方法，指导新型超高温多孔隔热材料微结构的构筑，发展材料的性能测试表征方法和性能匹配技术；一方面为研究材料在复杂热/力载荷下的热-力响应和高温失效机理提供分析依据，另一方面为多孔隔热材料的性能优化、合理使用以及寿命评估等提供精确指导。本项目属于前沿性的基础研究，其研究成果将进一步丰富和发展多孔材料强韧化的科学理论，同时为超高温多孔隔热材料在高超声速飞行器不同热防护系统的工程化应用提供技术支撑和理论依据。

超高温多孔隔热材料是新型高超声速飞行器热防护系统研制成败最为关键的技术之一。针对现有隔热材料与结构的耐温性和隔热性能不能兼顾的矛盾，本项目提出了微/纳孔复合结构的力学设计方法，研制了几种不同材料的超高温/超轻质多孔隔热材料，如氧化物纤维陶瓷、耐高温气凝胶复合氧化物纤维骨架和碳基超高温多孔隔热复合材料；发展了材料的性能测试表征方法和性能匹配技术；发展了µCT几何重构技术，建立多孔纤维隔热复合材料的微细观力学分析模型，揭示材料的热-力耦合失效机理。为超高温多孔隔热材料在高超声速飞行器不同热防护系统的工程化应用提供技术支撑和理论依据。