超声应力换能器指向性校准方法研究

超声应力换能器指向性对超声应力检测精度具有重要影响。该文提出了半圆柱试块法,被校换能器向半圆柱试块内部辐射声波,接收换能器在试块圆柱面各角度接收到信号,分析得到被校换能器的指向性。利用半圆柱试块法校准得到纵波换能器指向性,其-3 dB波束宽度为5.01°,这与水听器法测量值、理论值相对偏差分别为3.09%、2.66%。利用半圆柱试块法校准得到临界折射纵波换能器指向性,其-3 dB波束宽度为10.55°,这与仿真值相对偏差为2.23%。半圆柱试块法更符合超声应力的实际使用工况,不受换能器水密性、换能器工作原理等限制,适用于任意型号超声应力换能器,且校准更高效、快捷。

Study on Calibration of Directivity of Ultrasonic Stress Transducer

The directivity of ultrasonic stress transducer has an important influence on the accuracy of ultrasonic stress detection. In this paper, the semi-cylindrical block method is proposed. The transducer to be calibrated radiates sound waves to the interior of the semi-cylindrical block, and the receiving transducer receives the signals at various angles on the cylindrical surface of the block, and the directivity of the calibrated transducer is obtained by analysis. The directivity of the longitudinal wave transducer is calibrated by the semi-cylindrical block method, and its -3 dB beam width is 5.01°, the relative deviations from the measured value and theoretical value of the hydrophone method are 3.09% and 2.66%, respectively. The directivity of the critical refracted longitudinal wave transducer is obtained by the semi-cylindrical block method, and its -3 dB beam width is 10.55° and the relative deviation from the simulated value is 2.23%. The semi-cylindrical block method is more in line with the actual working conditions of ultrasonic stress, and is not limited by the water tightness of the transducer and the operating principle of the transducer. It is suitable for any type of ultrasonic stress transducer, and the calibration is more efficient and fast.