Enhancing Sensitivity of Vibration-based Damage Metrics using Feedback Control: Towards Dual Use Smart Structures

利用反馈控制提高基于振动的损伤度量的灵敏度：面向双重用途的智能结构本项目探索提高模态属性对局部损伤敏感性的方法，以便在智能结构中无创地自主检测损伤。智能结构包含嵌入式或表面安装的传感器和执行器，通常用于振动或声学控制。该项目的主要目标是开发和演示这些组件也可用于诊断和定位由于损坏而导致的结构退化的方法。第二个目标是将损伤检测与振动主动控制相结合，以开发多功能智能结构。控制系统的选择，包括确定结构的适当控制模型，量化标称不确定性，选择执行器和传感器的数量和位置，以及选择补偿器，在每个目标的背景下进行了研究。基于振动的损伤检测由于模态度量对局部损伤的敏感性小而变得复杂。该方案的假设是，仔细选择驱动结构的控制律，可以提高损伤引起的局部参数变化的可观测性。利用优化方法，建立了灵敏度增强控制律的设计分析框架，并将该控制律与减振目标相结合。针对灵敏度增强提出的指标包括模态频率、模态振型和机电阻抗。实验工作的重点是证明灵敏度提高控制板结构由均质材料。所开发的方法可应用于柔性结构或子结构的损伤自主检测与控制。例子包括空气动力学表面、飞机机身、建筑物和桥梁的子结构（如板、梁、壳）、旋转机械和薄壁管道。通过可靠的损伤检测方法和多功能智能部件，促进智能结构在各种应用中的经济使用和发展。

Laura R. Ray9988414Enhancing Sensitivity of Vibration-Based Damage Metrics using Feedback Control: Towards Dual Use Smart Structures This project explores methods of enhancing sensitivity of modal properties to local damage in order to detect damage noninvasively and autonomously in smart structures. Smart structures contain embedded or surface mounted sensors and actuators that are normally used for vibration or acoustic control. Developing and demonstrating methods by which these components can also be used to diagnose and localize structural degradation due to damage is the primary objective of the project. A second objective is to integrate damage detection and active vibration control in order to develop multifunctional smart structures. Choice of the control system, which encompasses determining an appropriate control model of the structure, quantifying nominal uncertainty, selecting number of and placement of actuators and sensors, and choosing a compensator, is investigated in the context of each objective. Vibration-based damage detection is complicated by the small sensitivity of modal metrics to local damage. The hypothesis of the project is that careful selection of control laws for actuating the structure can enhance observability of local parameter variations induced by damage. An analytic framework for designing sensitivity enhancing control laws and for integrating such systems with vibration damping objectives is developed using optimization. Proposed metrics targeted for sensitivity enhancement include modal frequencies, mode shapes, and electromechanical impedance. Experimental efforts focus on demonstrating sensitivity enhancing control for plate structures constructed from homogeneous materials. The methods under development have application to autonomous damage detection and control of flexible structures or substructures. Examples include aerodynamic surfaces, aircraft fuselage, building and bridge substructures (e.g., plates, beams, shells), rotating machinery, and thin-walled pipes. Through assured damage detection methods and multifunctional smart components, the research promotes economical use and development of smart structures in a variety of applications.