纤维增强层压柔性薄膜复合材料损伤演化机理研究

With the development and forthputting of near space, aircrafts such as the near space aerostat, stratosphric balloons, high altitude airships are increasingly becoming the hot research for many countries around the world. Floating gasbag is one of the key body structure for stratospheric balloon aircraft, and the damage mechanical properties of fiber-reinforced laminated composite envelope directly affects safety, reliability and service life of long-endurance work of the aircrafts. Based on the different typical damage modes of composite materials, the composite micro-mechanics theory is used to construct the fiber-reinforced laminated envelope film composite with the SEM experiment. Then with the method of continuum damage mechanics theory, the damage degree of the independent envelope film composites component is introduced to establish the damage evolution model of the damaged envelope film composites and the fatigue life of high and low temperature alternating fatigue estimating model. Furthermore, the stress and fatigue damage test of the warp and weft in uniaxial, biaxial and different off-axis direction are carried out to identify and verify the damage evolution parameters of the constructed theoretical model to reveal the damage evolution law of the fiber-reinforced laminated envelope composite, which is quite important and meaningful to develop high-performance envelope material and improve the using performance of the aircrafts. The project intends to expand the theoretical analysis of the damage evolution of fiber braided reinforced laminated composites and to promote the development of the theory of damage mechanics of flexible composites.

随着对临近空间资源的开发和利用，临近空间浮空器、平流层气球、高空飞艇等飞行器正成为世界各国研究的热点。作为临近空间飞行器的关键主体结构之一的浮空气囊，其纤维增强型层压型薄膜蒙皮材料的损伤演化特性直接决定飞行器长航时工作的安全性、可靠性和使用寿命。本项目从复合材料的典型损伤模式出发，首先采用复合材料细观力学理论，基于电子扫描电镜SEM试验构建蒙皮复合材料的无损本构模型，继而采用连续介质损伤力学理论方法，引入独立的蒙皮薄膜组分损伤度，建立含损伤的复合材料损伤演化模型和疲劳损伤寿命预估模型，并开展单轴、双轴以及不同偏轴向的应力疲劳损伤试验，辨识和验证所构建理论模型的损伤演化参数，以揭示纤维增强层压型蒙皮复合材料的损伤演化规律，对研究高性能薄膜蒙皮材料和提高飞行器的使用性能具有重要意义。本项目拟拓展纤维编织增强层压型薄膜复合材料损伤演化分析的理论方法，以推动柔性薄膜复合材料损伤力学理论的发展。

世界各国正在快速开发、争夺和利用临近空间高空资源，临近空间浮空器、平流层飞艇、高空飞艇等飞行器已经成为非常重要的研究热点。而影响临近空间飞行器的关键核心问题之一是浮空气囊，气囊层压型复合材料柔性薄膜的承载疲劳损伤演化特性直接决定飞行器长航时工作的安全性、可靠性和使用寿命。本项目综合采用理论建模、试验测试、数值计算等方法，以复合材料的典型损伤模式为基础，采用复合材料细观力学理论，结合电子扫描电镜SEM试验观测形貌，基于柔性薄膜纤维膜层、基体层、功能膜层的三种构成组分，建立了柔性薄膜蒙皮复合材料的无损本构模型，进而采用连续介质损伤力学理论方法，引入针对各组分的独立的损伤度参数，建立了含损伤的复合材料损伤演化模型和疲劳损伤寿命预估模型。同时开展了单轴、双轴以及不同偏轴向的应力疲劳损伤试验，辨识和验证所构建理论模型的损伤演化参数,利用有限元仿真柔性薄膜充气双轴向承载变形规律。研究结果揭示了用于浮空器的柔性纤维增强层压型薄膜复合材料的承载疲劳损伤演化规律，获得了柔性薄膜充气承载工况下的力学与变形特性，对研究高性能柔性薄膜蒙皮材料和提高临近空间飞行器的使用性能具有重要意义，也拓展了纤维编织增强层压型薄膜复合材料损伤演化分析的理论方法，有效促进了柔性薄膜复合材料损伤力学理论的发展。