Ono Kanji
Department of Materials Science and Engineering, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA.
Sensors (Basel). 2019 Jul 16;19(14):3129. doi: 10.3390/s19143129.
Acoustic emission (AE) sensors and ultrasonic transducers were characterized for the detection of Rayleigh waves (RW). Small aperture reference sensors were characterized first using the fracture of glass capillary tubes in combination with a theoretical displacement calculation, which utilized finite element method (FEM) and was verified by laser interferometer. For the calibration of 18 commercial sensors and two piezoceramic disks, a 90° angle beam transducer was used to generate RW pulses on an aluminum transfer block. By a substitution method, RW receiving sensitivity of a sensor under test was determined over the range of frequency from 22 kHz to 2 MHz. Results were compared to the sensitivities to normally incident waves (NW) and to other guided waves (GW). It was found that (1) NW sensitivities are always higher than RW sensitivities, (2) differences between NW and RW receiving sensitivities are dependent on frequency and sensor size, (3) most sensors show comparable RW and GW receiving sensitivities, especially those of commonly used AE sensors, and (4) the receiving sensitivities of small aperture (1 mm diameter) sensors behave differently from larger sensors.
对声发射（AE）传感器和超声换能器进行了表征，以检测瑞利波（RW）。首先使用玻璃毛细管的断裂结合理论位移计算对小孔径参考传感器进行表征，该理论位移计算采用有限元方法（FEM）并通过激光干涉仪进行了验证。为了校准18个商用传感器和两个压电陶瓷盘，使用90°角束换能器在铝质传输块上产生RW脉冲。通过替代法，在22 kHz至2 MHz的频率范围内确定了被测传感器的RW接收灵敏度。将结果与对垂直入射波（NW）和其他导波（GW）的灵敏度进行了比较。结果发现：（1）NW灵敏度总是高于RW灵敏度；（2）NW和RW接收灵敏度之间的差异取决于频率和传感器尺寸；（3）大多数传感器显示出相当的RW和GW接收灵敏度，特别是常用的AE传感器；（4）小孔径（直径1 mm）传感器的接收灵敏度与较大尺寸传感器的表现不同。
