极端环境下碳纤维增强复合材料结构的力学行为表征与评价

Advanced composite structures have been increasingly used as structural members in many structures such as missile, airplane, satellites et al. Hence, it is necessary to characterize and evaluate the mechanical behaviour of advanced composite structures used in airplane under its service environment, which in fight condition undergoes low temperature. In our project, a new measurement system based on Extended Digital Image Correlation system will be established to measure the deformation of the surface of the advanced composite structures under temperature at -60 C. Then,the mechanical behaviour of advanced composite structures and the onset and the evolution of the surface micro-cracks of the material will be investigated using this new measurement system. Further, the impact behaviour and the remaining load carrying capacity after impact for the advanced composite structures under low temperature will be investigate. Third, the FE model for simulating the static and impact behaviour of advanced composite structures under low temperature will be established and the FE model will be validated by the experimental results. Finally, the mechanical model for advanced composite structures under statics load and impact load at a low temperature will be developed and the damge model for this structure will also be established.

由于先进复合材料在航空航天器领域具有极其广泛的应用前景，同时考虑到航空航天飞行器需要服役在低温环境下，因而研究低温环境下先进复合材料的力学行为及性能是非常必要的。首先，本项目拟针对低温环境作用下的先进复合材料结构的表面变形问题，构建一套数字图像测试系统。其次，利用该系统研究层压结构和夹层结构复合材料表面的微裂纹扩展及损伤演化机制，分析受冲击作用的材料损伤容限。再次，建立低温环境下复合材料静载和冲击有限元模型并与实验结果进行对照，最后，构建先进复合材料结构在低温环境下受静载和冲击载荷的力学模型，并建立相应的损伤破坏准则。

先进复合材料在航空航天领域有着广阔的应用前景，研究其在常温以及低温环境下的力学行为具有重要的意义。本项目构建了一套适用于复合材料结构表面变形的数字图像相关系统，并利用该系统重点研究了含冲击分层损伤的CFRP复合材料层合板结构屈曲及后屈曲力学行为，以及伴随屈曲行为的复合材料结构表面损伤的损伤机理及其微裂纹扩展规律，并在理论推导、实验测试和数值计算三个方面进行了深入研究，建立了相关的损伤和破坏准则。建立了低温数字图像相关测试系统并进行了复合材料薄膜在-60℃~常温下的力学性能研究，分析了力学性能随温度的变化规律，为材料的低温力学性能测试与表征提供了可靠的技术保障。针对材料的断裂性能测试问题，对裂纹尖端不连续变形场的测试进行了扩展数字图像相关方法的裂尖位移函数的表征研究。值得注意的是，残余应力是影响材料力学性能的潜在有害因素，为此本项目结合数字图像相关方法全场变形测量的优势进行了残余应力测量方法的扩展研究，并得到了可靠的测试验证。