面向小子样热端部件的概率故障物理可靠性分析与评估

Research on fatigue reliability of hot section components is a primary work to ensure the safety of aircrafts. Traditional fatigue reliability theories and methods cannot deal with hierarchical information fusion, time-variant loading and dynamic environmental interaction as well as the interaction and competition of multiple failure mechanisms of hot section components under small sample conditions. . According to these issues, taking the aircraft turbine blades as the object of study, this project researches on Physics of Failure (PoF)-based reliability analysis and assessment methods of hot section components through hybrid uncertainty quantification and damage modeling of multiple failure mechanisms. Aiming at the following goals: Firstly, an efficient uncertainty quantification and propagation method is presented to deal with small sample, multi-sources and hierarchical information by using hierarchical Bayesian theory and PoF technique; Secondly, an unified method for damage estimation under multiple failure mechanisms (including fatigue, creep and high temperature oxidation) is put forward through investigating the interaction and competition behavior of materials under fatigue tests with time-variant loading, which considers the environmental effects on crack initiation and propagation mechanisms; Then, a PoF-based time-variant reliability analysis and assessment method based on damage accumulation interference under multiple failure mechanisms is developed to account for the scatter and randomness of material properties, internal defects, loading histories and performance degradation of hot section components. . Finally, PoF-based reliability analysis and assessment theories and methods will be established for hot section components under small sample conditions, which offer a theoretical basis and technical support to improve the reliable life prediction, health management and optimal maintenance decision of aircraft engines.

航空发动机热端部件的疲劳可靠性研究是保证飞机安全运行的基础，而传统疲劳可靠性理论与方法难以应对小子样热端部件寿命可靠性设计与分析中的多源不确定信息处理、时变载荷/环境交互作用、多重损伤（疲劳、蠕变、氧化）耦合干涉等问题。针对此，本项目以航空发动机涡轮叶片为研究对象，对耦合多重损伤交互作用与混合不确定性量化的故障物理可靠性分析与评估方法展开研究。通过将层次Bayes理论与故障物理技术相结合，研究小子样、多源、跨层级不确定信息的量化、传递与融合方法；试验研究时变载荷/环境作用下的多重损伤耦合竞争失效机理，提出包含环境效应的多重损伤累积破坏统一描述模型；通过研究材料属性、内部缺陷、载荷历程、性能退化等因素的动态规律，建立基于多重损伤耦合干涉的概率故障物理时变可靠性评估方法，形成面向小子样热端部件的故障物理可靠性分析与评估理论和方法，为航空发动机可靠定寿、健康管理和最优维修决策提供理论和技术支撑。

航空发动机热端部件的疲劳可靠性研究是保证飞机安全运行的基础，而传统疲劳可靠性理论与方法难以应对小子样热端部件寿命可靠性设计与分析中的多源不确定信息处理、时变载荷/环境交互作用、多重损伤耦合作用等问题。针对此，本项目以航空发动机涡轮部件为研究对象，开展了耦合多重损伤交互作用与混合不确定性量化的故障物理可靠性分析与评估方法研究，其主要研究内容及成果如下：（1）发展了面向热端部件定寿中随机不确定性和认知不确定性的混合不确定性量化方法，提出了综合考虑材料分散性、使役差异性以及制造质量波动性的疲劳可靠性设计与评估方法；（2）阐明了内部、表面位置缺陷下裂纹萌生、扩展及融合失效机制，提出了尺寸效应下耦合缺陷特性分析与裂纹扩展的构件疲劳强度评估方法；（3）提出了耦合临界面-应变能的多轴疲劳寿命预测模型，该模型损伤参量考虑了平均应力效应；（4）从能量耗散的角度定义了表征缺口局部损伤程度的“场”概念，提出了多轴缺口疲劳寿命预测的能量场强法；（5）探讨了耦合多轴疲劳分析的临界平面法与缺口疲劳分析的临界距离理论用于多轴缺口疲劳分析的可行性，确定了临界平面法和临界距离理论的最佳耦合次序；（6）阐明了尺寸效应下裂纹萌生、扩展及多裂纹融合失效机制，揭示了尺寸效应下多裂纹融合概率随裂纹密度和循环周次的变化规律；（7）提出了随应力水平变化的高应力体积模型，阐明了最弱链理论下考虑尺寸效应的疲劳可靠性传递机制；（8）构建了融合疲劳机理分析与不确定性量化的概率疲劳寿命预测框架，发展了故障物理可靠性理论方法，为热端结构设计、安全评定和健康评估提供了理论依据和方法支撑。. 研究已发表标注基金号的学术论文43篇，另有5篇论文待发表，被SCI收录42篇，含特邀综述论文2篇、中国百篇最具影响国际学术论文1篇和ESI高引论文17篇。近两年，受邀作国内外学术会议大会主题报告4次。申请发明专利8项，已授权7项。项目负责人于2019年获欧洲结构完整性协会（ESIS）-TC12卓越成就奖，2020年获Fatigue Fract Eng Mater Struct国际期刊高被引论文奖，获国际会议最佳论文奖2次。自2018年起，项目负责人连续入选Elsevier中国高被引学者；2020年，入选美国斯坦福大学发布的全球Top 2%科学家。项目共培养博士生3名和硕士生11名。.