设计了一种夹心式纵弯复合振动模式超声换能器,该换能器由纵向夹心式压电超声换能器与弯曲正六边形薄板组成。采用有限元方法,对一定几何尺寸边界自由的正六边形薄板进行模态分析,得到中心位移最大的某一模态,设计以该模态的频率作为共振频率的纵弯复合模式换能器。当复合振动系统振动模式的共振频率与纵向换能器的共振频率以及正六边形薄板弯曲振动的共振频率一致时,复合振动系统具有较高的有效机电耦和系数,系统声辐射能力较强;频率的理论与测量值的误差可能是设计纵向换能器时未考虑预应力螺栓、前后盖板的形状以及横向振动的影响.材料参数的取值与实际值有误差。弯曲振动的正六边形薄板的几何尺寸大,将会增大复合振动系统声波的辐射面积,因此可以改善局部空化腐蚀问题,并且可以提高槽内声场的均匀性,从而可以提高声化学产率;实验结果表明,换能器的共振频率测试值与设计值基本吻合。
In this paper, a longitudinal-flexural composite mode ultrasonic transducer composed of the sandwich longitudinal mode ultrasonic transducer and the flexural regular hexagon plate is studied. The FEM (finite element method) is adopted to analyze the pattern of the regular hexagon plates, which have a certain geometric size and a free border, and then get a pattern having the largest central displacement A longitudinal-flexural composite mode ultrasonic transducer is designed with the pattern's frequency as the resonance frequency. The experiment shows that the measured frequency is in agreement with the calculated one.