双激励全波长压电陶瓷超声换能器工作特性分析

对由两个半波长夹心式压电陶瓷换能器级联而成的双激励全波长压电陶瓷超声换能器进行了研究,给出了这种换能器优值的相关参量表达式,通过数值计算分析了该换能器的结构和材料参数对其特性的影响。研究结果表明,当两组压电陶瓷堆分别位于各自所在半波长换能器的位移节点,或者在压电陶瓷片数量确定情况下两组压电陶瓷堆的片数相同时,换能器均能得到最大的优值;在相当大的范围内增加压电陶瓷片的数量,换能器的优值稍有降低,但力因子迅速增大;金属块材料对换能器的优值影响甚微。可见双激励全波长换能器能在不明显降低换能器综合性能的情况下有效增加压电陶瓷的体积,因而可大幅提高换能器的功率容量和负载能力,更适用于大功率重负载的场合。 

Operating characteristics analysis of a dual-excited full-wavelength piezoceramic ultrasonic transducer

A dual-excited full-wavelength piezoceramic ultrasonic transducer as a cascade of two half-wavelength sandwich piezoceramic transducers is studied. The relevant parameters' expressions of the figure of merit N for the transducer are derived, and the effects of the structure and material parameters of the transducer on its characteristics are further analyzed by numerical calculation. The results show that when the two piezoceramic stacks are respectively located at the displacement nodes of their own half-wavelength transducers, or the two piezoceramic stacks have the same number of pieces in the case of a certain number of piezoceramic pieces, the figure of merit of the transducer can reach a maximum. With increasing of the number of piezoceramic pieces in a fairly large range, the figure of merit of the transducer slightly decreases, but the force factor of the transducer increases rapidly. The metal materials of the transducer have little effect on its figure of merit. Thus it can be seen that the dual-excited full-wavelength transducer can effectively increase the volumes of the piezoceramic stacks in the case of that the transducer's comprehensive performance has only a little bit of degradation, so it's power capacity and load capability can be dramatically improved, which means the transducer is more suitable for high power and heavy load applications.