中文摘要：

研究了多模耦合宽频带复合换能器，结果发现，这种换能器在空气中的纵弯振动具有明显的规律性。针对1-3型压电复合材料，采用有限元法研究了压电陶瓷体积分数对换能器共振频率的影响，并研究了换能器共振频率与其几何尺寸间的关系。结果表明，换能器共振频率与压电陶瓷体积分数及其几何尺寸有关，即随压电陶瓷体积分数增加，共振频率增大；换能器前盖板几何尺寸越大，共振频率越小，纵振基频与弯振基频间距亦随之减小。

英文摘要：

After investigating the multi-mode wideband composite transducer, it has been found that the flexural and longitudinal vibration of this kind of transducer in air has significant regularity. For 1-3 type piezo-composite material used as the piezoelectric stack, the effect of the volume-fraction of piezoelectric ceramic on the resonant frequency has been studied by using the commercial finite element method and the relationship between the resonant frequency of the transducer and its dimension has also been studied in this paper. The results show that the resonant frequency of transducer will become higher with increase of volume fraction; and will become lower with increase of the dimension of front layer of transducer, and the resonant frequency is lower, the interval of longitudinal and flexural fundamental frequencies will be smaller.