基于激光全息法的聚焦换能器近场声特性分析

研究了基于激光全息法的低频聚焦换能器近场测量方法,分析了利用激光全息法测量近声场特性时的基本原理,构建了一套实验测量系统。为验证该方法的可行性与准确性,利用激光测振仪对1个由25个压电小柱按5×5排布构成,频率为80kHz且表面带有自聚焦声透镜的聚焦换能器的声场进行实验测试和推算,获得了距离该换能器辐射凹面中心50mm处振动膜片上的声压幅度和相位分布,推算出此聚焦换能器声轴线上的声压分布与焦点处声压分布,同时使用COMSOL模型仿真与水听器测试,对比验证了激光全息近场测量后远场外推结果的高准确性。

Study on Near-field Sound Pressure of Frequency Focusing Transducer Based on Laser Holography

Based on laser holography, the near-field measurement method of low-frequency focusing transducer was researched, the basic principle of laser holography to measure near-field characteristics was analyzed, and a set of experimental measurement system was constructed. In order to verify the feasibility and accuracy of this method, the sound field of a focusing transducer composed of 25 piezoelectric columns arranged in 5*5 with a frequency of 80kHz and a self focusing acoustic lens on the surface was experimentally tested and calculated by using a laser vibrometer, and the sound pressure amplitude and phase distribution on the vibrating diaphragm 50mm away from the center of the radiation concave surface of the transducer were obtained.Using COMSOL model simulation and hydrophone test, the comparison verifies the high accuracy of the far-field extrapolation results after the laser holographic near-field measurement.