临近空间飞行器C/SiC热防护结构损伤定位的模态声发射理论与方法研究

A catastrophic accident may be caused for the near spacecraft due to the damage occurred in C/SiC thermal protection structure. The modal acoustic emission technology owns considerable advantages in damage detection of C/SiC composite structures since it can evaluate the condition of the damage online by using the information contained in damage. However, it is hard to introduce the modal acoustic emission technology to the damage localization in C/SiC thermal protection structure because of the two main problems. The first factor is that the behavior of acoustic emission wave propagation in thermal protection structure is unknown, while the other one is lack of effective acoustic emission source location method considering the influence of interface. In order to solve the above problems, this project aims to establish a simulation method which can be used to study the characteristics of acoustic emission wave propagation in C/SiC composite structures accurately quantitatively, and then to reveal the principle of acoustic emission wave propagation in the C/SiC composite structure with cross-isolation interface. It is also possible to obtain the influence mechanism of the interface. Moreover, an modal acoustic emission source location method by isolation for C/SiC thermal protection structure is proposed, which is especially for the damage in the structure with interface. The results of this research project will provide a damage source location and isolation method for C/SiC thermal protection structure with efficient performance, and it is beneficial for the development of acoustic emission technology.

临近空间飞行器上的C/SiC复合材料热防护结构的损伤可能引起灾难性事故的发生。模态声发射技术可基于损伤自身信息，在线评估结构内部损伤的发生及位置，在C/SiC结构损伤检测领域中有良好的应用前景。然而，现今主要有两方面因素严重制约了模态声发射技术在C/SiC结构损伤定位中的应用：①带连接界面的C/SiC复合材料结构中声发射波传播规律不明；②缺乏考虑连接界面影响的声发射源隔离与定位方法。本项目拟针对上述问题构建C/SiC复合材料结构的声发射波传播特性精确定量仿真方法，可用于揭示带连接界面的C/SiC复合材料结构中的声发射波传播规律，获取声发射波传播的界面效应特性；在此基础上建立考虑连接界面影响的C/SiC热防护结构的声发射源隔离与定位方法。本项目的研究成果将为临近空间飞行器C/SiC复合材料热防护结构的在线损伤评估提供有效的技术方法，促进声发射检测理论的发展和方法的进步。

本项目以航空、航天等领域广泛使用的C/SiC复合材料结构为研究对象，针对C/SiC复合材料结构损伤声发射波的传播特性及损伤隔离与定位的关键问题，采取理论建模、分析、仿真计算与实验相结合的方法，建立了临近空间飞行器热防护结构损伤的声发射波传播特性的精确定量仿真方法；然后建立了强噪声环境下基于微观损伤机理的C/SiC复合材料结构损伤声发射监测方法，实现了C/SiC热防护系统的损伤监测；在此基础上建立了存在连接界面情况下的C/SiC复合材料结构的声发射源隔离与定位方法，实现损伤源的准确定位，最终建立了基于损伤监测的C/SiC复合材料结构健康管理关键技术体系。该项目为飞行器的结构完整性研究奠定基础，对于保障飞行器全寿命周期内的安全性具有重要现实意义和价值。通过以上研究，发表学术论文10篇，SCI收录4篇，会议论文6篇，相关成果申请并获受理6项；研究成果有力支撑了工程型号研制、相关预研课题立项，解决了若干关键技术问题，推动了声发射技术在工程型号中的成功应用。在基金项目的支持下，项目主持人获评中国航天科工集团公司青年创新型优秀人才计划。