压电陶瓷非线性对大功率换能器结构参数匹配影响的计算分析

在Guyomar非线性模型基础上，通过机电等效法将晶堆前向负载作为等效质量和阻尼加入振动方程的质量项和阻尼项，推导了换能器振速、辐射声压级和谐振频率偏移率等表达式，计算分析了压电陶瓷非线性参数和结构参数对换能器声辐射性能的影响，研究了压电陶瓷的非线性对换能器结构参数匹配的影响。结果表明，换能器节面靠前，前盖板厚度越小，前盖板大径越小，都可以减少压电陶瓷非线性引起的换能器频率偏移。当设计频率确定时，压电陶瓷处于非线性工作域的换能器的结构参数有所减小。换能器加入辐射端匹配后，可以改善压电晶堆前向负载匹配，降低换能器的谐振频率偏移率。换能器激励电流也会出现频率偏移现象。在提高换能器激励电压时，换能器的结构参数应适当减小。得到的结论可为换能器设计提供理论依据和帮助。

Computational analysis of influence of piezoelectric ceramic nonlinearity on structural parameter matching of high power transducers

On the basis of Guyomar nonlinear model, the forward load of the crystal stack is added as the equivalent mass and damping into the mass and damping terms of the model by the electromechanical equivalent method, thus the vibration velocity, radiation sound pressure level and frequency offset of the transducer are deduced. The influence of nonlinear parameters and structural parameters of piezoelectric ceramics on the acoustic radiation performance of the transducer is calculated and analyzed. And the influence of the nonlinearity of piezoelectric ceramics on the matching of structural parameters of the transducer is analyzed. The results show that when the nodal surface of the transducer is forward, the thickness of the front cover is smaller, and the major diameter of the front cover is smaller, which can reduce the frequency offset of the transducer caused by the nonlinearity of piezoelectric ceramics. When the design frequency is determined, the structural parameters of the transducer are reduced. After adding radiation end matching to the transducer, the forward load matching of the piezoelectric crystal stack can be improved, and the resonant frequency offset rate of the transducer can be reduced. The transducer excitation current also exhibits nonlinear frequency offset. When increasing the excitation voltage of the transducer, the structural parameters of the transducer should be appropriately reduced. The obtained conclusions can provide theoretical basis and help for transducer design.