航空时变服役条件下复杂结构的损伤波动诊断

Aircraft structural health monitoring is capable of monitoring the structural state during the process of manufacture, test and service. Hence, it can be used to ensure the application of new material, instruct the reliability design and reduce the maintenance cost, which results in improving the reliability of aircraft structure. The elastic wave based damage diagnosis of complex aircraft structures under in-service time-varying conditions will be studied in this project, which is an important issue for the development and application of aircraft structural health monitoring. The rule and mechanism of mechanics influence of elastic wave based damage diagnosis, which are introduced by the in-service time-varying conditions, will be revealed first. The influence mechanism of the elastic wave features, which is introduced by the coupling of complex structure styles with time-varying factors, will be studied in detail, as well as the uncertainty distributions of the elastic wave features in these situations. The representing method of the structural state feature will be proposed by fusing damage features of linear wave, non-linear wave and multi-channel monitoring information of the local sensor network. The elastic wave based modeling method of dynamic probability will be presented for complex aircraft structures. Based on the method, the probabilistic diagnosis mechanism of damage under time-varying conditions will be put forward. Experiments on coupons, components and full-scale aircrafts will be performed to validate the effectiveness of the proposed methods. The project aims at solving the difficulty of reliable damage diagnosis of performing structural health monitoring methods in the engineering application. Based on the development of the above theories and methods, engineering systems will be developed to promote the application of the structural health monitoring technology on important aircrafts.

航空结构健康监测可以在飞行器的设计、实验和服役全过程中对结构状态进行监测，因此可以保障新材料应用、指导结构可靠性设计，从而提高结构的可靠性。本项目围绕关键科学问题“航空时变服役条件下复杂结构的损伤波动诊断”开展研究。揭示时变航空服役条件对损伤波动诊断的力学影响机理和规律；研究并获取复杂结构-时变因素对弹性波特征的混合影响机制及弹性波特征不确定性分布规律；提出融合弹性波损伤线性及非线性特征、传感器局域网络多路径信息的结构状态特征获取方法；提出面向复杂航空结构的弹性波-动态概率建模方法及基于该方法的时变条件下的损伤概率诊断机制；并通过零件级、部件级及全机飞机结构损伤监测验证上述方法的有效性，以解决波动结构健康监测方法在航空工程应用中所面临的可靠诊断难点，同时研发工程应用系统，推动航空结构健康监测理论的发展及在飞行器型号上的应用。

飞行器装备是国民经济发展和国防安全保障的国之重器，结构作为装备的基本承载和气动构型单元，其安全是重中之重，其可靠性维护是充分发挥飞行器效能、提升经济性、避免重大浪费的重要保障。航空结构健康监测可以实现飞行器结构损伤的快速在线诊断，可有效提升安全、效能和经济性。但工程应用中，复杂航空服役条件对航空结构损伤的准确诊断带来严重影响。项目围绕制约航空结构健康监测应用的关键科学问题“航空时变服役条件下结构的损伤波动诊断”开展研究。.主要研究进展和创新点如下：1.系统研究并揭示了温度、载荷等典型航空时变因素对结构损伤诊断的影响机理和规律，提出融合弹性波线性及非线性特征及基于传感器网络多路径信息融合成像的复杂结构损伤诊断机制；2.提出并建立了弹性波-高斯过程、弹性波-高斯混合模型、弹性波-隐马尔可夫模型、弹性波-粒子滤波融合4种强时变因素耦合作用下的结构状态动态概率建模方法，提出基于模型状态迁移表征的损伤定量化诊断及成像机制，实现了强时变耦合因素作用下裂纹及分层等典型损伤的准确诊断；3.针对结构长期服役所面临的动态时变耦合影响难以事先获取的难题，提出了动态概率损伤诊断模型的在线更新与定量化标定机制，结合先验模型、在线监测特征及维护数据实现诊断模型的在线更新及标定，解决了被监测结构长期服役中的损伤准确诊断问题。.项目研发了弹性波结构健康监测系列装备，被近20个单位购买，先后应用于10多个重大军民用型号飞机设计、试验、维护及延寿，并实现了飞行应用，推动了弹性波结构健康监测方法从基础理论到实际应用新技术的转化。发表学术论文97篇，授权国际、国家发明专利22项，项目负责人获国际结构健康监测年度人物奖（美国，国内航空领域学者首次获奖）、2人次入选国家级人才，获江苏省科学技术一等奖，中国航空学会优秀博士学位论文1篇。