Soman Rohan, Kim Jee Myung, Boyer Alex, Peters Kara
Institute of Fluid Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gdansk, Poland.
Department of Mechanical and Aerospace Engineering, North Carolina State University, Campus Box 7910, Raleigh, NC 27695, USA.
Sensors (Basel). 2024 Sep 30;24(19):6354. doi: 10.3390/s24196354.
Guided waves (GW) allow fast inspection of a large area and hence have received great interest from the structural health monitoring (SHM) community. Fiber Bragg grating (FBG) sensors offer several advantages but their use has been limited for the GW sensing due to its limited sensitivity. FBG sensors in the edge-filtering configuration have overcome this issue with sensitivity and there is a renewed interest in their use. Unfortunately, the FBG sensors and the equipment needed for interrogation is quite expensive, and hence their number is restricted. In the previous work by the authors, the number and location of the actuators was optimized for developing a SHM system with a single sensor and multiple actuators. But through the use of the phenomenon of acoustic coupling, multiple locations on the structure may be interrogated with a single FBG sensor. As a result, a sensor network with multiple sensing locations and a few actuators is feasible and cost effective. This paper develops a two-step methodology for the optimization of an actuator-sensor network harnessing the acoustic coupling ability of FBG sensors. In the first stage, the actuator-sensor network is optimized based on the application demands (coverage with at least three actuator-sensor pairs) and the cost of the instrumentation. In the second stage, an acoustic coupler network is designed to ensure high-fidelity measurements with minimal interference from other bond locations (overlap of measurements) as well as interference from features in the acoustically coupled circuit (fiber end, coupler, etc.). The non-sorting genetic algorithm (NSGA-II) is implemented for finding the optimal solution for both problems. The analytical implementation of the cost function is validated experimentally. The results show that the optimization does indeed have the potential to improve the quality of SHM while reducing the instrumentation costs significantly.
导波（GW）能够快速检测大面积区域，因此受到了结构健康监测（SHM）领域的广泛关注。光纤布拉格光栅（FBG）传感器具有诸多优点，但由于其灵敏度有限，在导波传感中的应用受到了限制。边缘滤波配置的FBG传感器在灵敏度方面克服了这一问题，人们对其应用重新产生了兴趣。不幸的是，FBG传感器及其询问所需的设备相当昂贵，因此其数量受到限制。在作者之前的工作中，对激励器的数量和位置进行了优化，以开发一种具有单个传感器和多个激励器的SHM系统。但是，通过利用声耦合现象，结构上的多个位置可以用单个FBG传感器进行询问。因此，具有多个传感位置和少量激励器的传感器网络是可行且具有成本效益的。本文提出了一种两步法，用于优化利用FBG传感器声耦合能力的激励器 - 传感器网络。在第一阶段，基于应用需求（至少三个激励器 - 传感器对的覆盖范围）和仪器成本对激励器 - 传感器网络进行优化。在第二阶段，设计一个声耦合器网络，以确保在最小化来自其他粘结位置的干扰（测量重叠）以及来自声耦合电路中的部件（光纤末端、耦合器等）的干扰的情况下进行高保真测量。采用非支配排序遗传算法（NSGA-II）来求解这两个问题的最优解。通过实验验证了成本函数的解析实现。结果表明，这种优化确实有潜力在显著降低仪器成本的同时提高SHM的质量。
