This paper investigates the free vibration characteristics for piezoceramic bimorphs in series connections by using theoretical analysis, numerical calculation, and experimental measurement. Series- and parallel-type piezoceramic bimorphs under fully-clamped boundary conditions are analyzed in this study. The theoretical solutions are derived base on the Mindlin's plate theory to explore the coupled out-of-plane (transverse) and in-plane (planar) resonant vibration characteristics; the numerical calculations based upon finite-element method are also performed and agree very well with the theoretical results for resonant frequency and corresponding mode shape. Two optical techniques, amplitude- fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV), and an impedance analysis are used to validate the theoretical and numerical results. It is shown that there is no difference between theoretical and numerical results regarding vibration characteristics of series- and parallel-type piezoceramic bimorphs. However, the experimental findings obtained by impedance analysis reveal that the boundary condition plays an important role for the excited vibration modes of parallel-type piezoceramic bimorphs. The imperfect clamped-circumference simulation in experimental procedure will result in some unexpected vibration modes arising, which can be distinguished between out-of-plane and in-plane modes by AF-ESPI measurement.

本文通过理论分析、数值计算和实验测量研究了串联压电陶瓷双压电晶片的自由振动特性。本研究分析了完全夹紧边界条件下的串联和并联型压电陶瓷双压电晶片。理论解是基于Mindlin的板理论推导出来的，以探索耦合的面外（横向）和面内（平面）共振振动特性；还进行了基于有限元方法的数值计算，并且与谐振频率和相应模式形状的理论结果非常吻合。两种光学技术，振幅波动电子散斑干涉仪（AF-ESPI）和激光多普勒测振仪（LDV），阻抗分析用于验证理论和数值结果。结果表明，关于串联和并联型压电陶瓷双压电晶片的振动特性，理论和数值结果之间没有差异。然而，通过阻抗分析获得的实验结果表明，边界条件对平行型压电陶瓷双压电晶片的激发振动模式起着重要作用。实验过程中不完善的夹紧周长模拟会导致一些意外的振动模式出现，可以通过 AF-ESPI 测量区分面外和面内模式。结果表明，关于串联和并联型压电陶瓷双压电晶片的振动特性，理论和数值结果之间没有差异。然而，通过阻抗分析获得的实验结果表明，边界条件对平行型压电陶瓷双压电晶片的激发振动模式起着重要作用。实验过程中不完善的夹紧周长模拟会导致一些意外的振动模式出现，可以通过 AF-ESPI 测量区分面外和面内模式。结果表明，关于串联和并联型压电陶瓷双压电晶片的振动特性，理论和数值结果之间没有差异。然而，通过阻抗分析获得的实验结果表明，边界条件对平行型压电陶瓷双压电晶片的激发振动模式起着重要作用。实验过程中不完善的夹紧周长模拟会导致一些意外的振动模式出现，可以通过 AF-ESPI 测量区分面外和面内模式。