Yu Fengming, Okabe Yoji
Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan.
Sensors (Basel). 2017 Dec 14;17(12):2908. doi: 10.3390/s17122908.
Recently, the authors have proposed a remote acoustic emission (AE) measurement configuration using a sensitive fiber-optic Bragg grating (FBG) sensor. In the configuration, the FBG sensor was remotely bonded on a plate, and an optical fiber was used as the waveguide to propagate AE waves from the adhesive point to the sensor. The previous work (Yu et al., Smart Materials and Structures 25 (10), 105,033 (2016)) has clarified the sensing principle behind the special remote measurement system that enables accurate remote sensing of AE signals. Since the silica-glass optical fibers have a high heat-resistance exceeding 1000 °C, this work presents a preliminary high-temperature AE detection method by using the optical fiber-based ultrasonic waveguide to propagate the AE from a high-temperature environment to a room-temperature environment, in which the FBG sensor could function as the receiver of the guided wave. As a result, the novel measurement configuration successfully achieved highly sensitive and stable AE detection in an alumina plate at elevated temperatures in the 100 °C to 1000 °C range. Due to its good performance, this detection method will be potentially useful for the non-destructive testing that can be performed in high-temperature environments to evaluate the microscopic damage in heat-resistant materials.
最近，作者们提出了一种使用灵敏光纤布拉格光栅（FBG）传感器的远程声发射（AE）测量配置。在该配置中，FBG传感器被远程粘贴在一块板上，并且使用光纤作为波导将AE波从粘贴点传播到传感器。先前的工作（Yu等人，《智能材料与结构》25（10），105,033（2016））已经阐明了这种特殊远程测量系统背后的传感原理，该系统能够对AE信号进行精确的远程传感。由于石英玻璃光纤具有超过1000°C的高耐热性，这项工作提出了一种初步的高温AE检测方法，即利用基于光纤的超声波波导将AE从高温环境传播到室温环境，在室温环境中FBG传感器可作为导波的接收器。结果，这种新颖的测量配置在100°C至1000°C范围内的高温下成功地在氧化铝板中实现了高灵敏度和稳定的AE检测。由于其良好的性能，这种检测方法对于在高温环境中进行的无损检测以评估耐热材料中的微观损伤可能会很有用。
