梯度匹配层宽带换能器的理论与数值模拟

Theoretical and Numerical Simulation of Broadband Transducer With Gradient Matching Layers

传统的λ/4(λ为波长)共振透射的匹配技术所制备的匹配层已不能满足当前业界对高性能的要求。该文从理论上研究了一维变梯度密度材料和变截面波导管两种梯度阻抗匹配层模型的声传播情况,推导出阻抗梯度渐变材料的声能透射率。对多种形状变截面管道进行了数值模拟,分析了匹配层厚度及截面形状对透射率的影响。数值结果表明,变截面管道匹配层具有在高频声强全部透射的性能,且匹配层越厚,低频截止频率越低,用作超声波换能器的匹配层能提升换能器的性能。

The matching layers prepared by the conventionalλ/4(λis the wavelength)resonant transmission matching technology can’t meet the high performance requirements in the current industry.In this paper,the acoustic propagation of two kinds of gradient impedance matching modelsof one-dimensional variable-gradient density material and variable cross-section waveguidesare studied theoreticallyand the acoustic energy transmittance of impedance gradient graded material is derived.Then the variable cross-section waveguides with a variety of shapes are numerically simulated,and the effects of matching layer thickness and cross-section shape on the transmittance are analyzed.The numerical simulation results show that the matching layer with variable cross-section waveguides has all transmission performance at high frequency acoustic intensity and the thicker the matching layer,the lower the low-frequency cut-off frequency.The performance of the ultrasonic transducer can be improved by using the proposed matching layer with variable cross-section waveguides.