CAREER: Vibration-Based Active and Passive Damage Identification of Time-Varying Dynamical Systems with Applications to Rotating Structures

该学院早期职业发展（CAREER）研究计划的目的是开发基于振动的损伤识别策略，这些策略严格适用于时变动力系统。结构健康监测是许多关键工程系统提高安全性和可靠性的关键技术。基于监测结构的模态特性的变化的策略是有吸引力的，由于其非破坏性的性质和能力，以评估全球结构健康从有限的传感器信息。目前基于振动的损伤识别策略的发展主要依赖于经典的特征向量分解，其中假定测量的反应谱与结构的真实固有频率具有时不变的对应关系。一个重要的系统类别，这种关系不成立的周期性时变动力系统。主要的例子是转子动力结构，如涡轮机、轴、螺旋桨、齿轮系和泵。这种更复杂的，时变的，光谱的行为构成了一个重大的挑战，损伤估计，必须找到一个合适的逆关系，测量光谱的变化，在结构系统参数的变化。 该项目将开发基于广义时变模态分解框架和新型Floquet乘数损伤灵敏度范例的新方法。这些新的配方将使估计的严重程度和位置的多个同时发生的结构损伤的系统固有的时变动态行为直接从测量的时域或频率响应信息。对于装有力致动器的转子动力系统，将探索基于Floquet特征向量配置和周期反馈控制的新的、积极增强的损伤估计策略。在多种控制调谐下进行损伤识别，将有效地丰富数据集，弥补有限的传感器信息，提高空间损伤分辨率，对提高依赖于关键旋转机械的基础设施、交通运输和航空航天系统的安全性和可靠性具有重要意义。通过提供一个新的分析基础的一大类时变动力系统的损伤估计，这项研究将推进实时的发展，在原位，方法预测incipit系统故障，并允许增加操作安全裕度。此外，研究结果将有显着的影响，广泛的控制和信号处理的应用程序中涉及时变动力系统。该项目还涉及一个全面的教育计划，利用研究和实验室演示作为切入点，以激励和激励有前途的学生追求科学事业。高中外展活动将通过田纳西大学的高中工程系统介绍（HITES）计划进行，并将对田纳西州东部地区的教育产生宝贵的影响。

The aim of this Faculty Early Career Development (CAREER) research program is to develop vibration based damage identification strategies which are rigorously suited for time-varying dynamical systems. Structural health monitoring is a key technology for enhancing safety and reliability in many critical engineering systems. Strategies based on monitoring changes in a structure's modal characteristics are attractive due to their non-destructive nature and ability to assess global structural health from limited sensor information. The current evolution of vibration based damage identification strategies largely depend on classical Eigenvector decomposition, where it is presumed that the measured response spectrum has a time invariant correspondence with the true natural frequencies of the structure. One important class of systems where this relationship does not hold is for periodically time varying dynamical systems. Prime examples are rotordynamic structures, such as turbines, shafts, propellers, gear-trains and pumps. This more complex, time varying, spectral behavior poses a significant challenge for damage estimation where a suitable inverse relation must be found to relate measured spectral changes to changes in structural system parameters. This project will develop new methods based on a generalized time-varying modal decomposition framework coupled with a novel Floquet multiplier damage sensitivity paradigm. These new formulations will enable estimation of the severity and location of multiple simultaneous structural damages in systems with inherently time varying dynamical behavior directly from measured time domain or frequency response information. For rotordynamic systems equipped force actuators, new, actively enhanced, damage estimation strategies based on Floquet Eigenvector assignment and periodic feedback control will be explored. Performing damage identification under multiple control tunings, will effectively enrich the data set and thereby compensate for limited sensor information and allow for increased spatial damage resolution.This research will have an important impact on enhancing the safety and reliability of many infrastructures, transportation and aerospace systems which rely on critical rotating machinery. By providing a new analytical foundation for damage estimation of a large class of time varying dynamical systems, this research will advance the development of real-time, in-situ, methods for prediction of incipit system failures and allow for increased operating safety margins. Additionally, the research results will have significant implications for a wide array of control and signal processing applications where time varying dynamical systems are involved. This project also involves a comprehensive educational plan which utilizes the research and laboratory demonstrations as an entree point to motivate and inspire up-and-coming students to pursue a scientific career. High school outreach activities will be conduced through the High School Introduction to Engineering Systems (HITES) program at the University of Tennessee and will have a valuable influence on education in the greater East Tennessee region.