Electromechanical coupling efficiency of transverse vibration in piezoelectric plates according to electrode configuration

Abstract

This study proposes a method of configuring electrodes for piezoelectric plates to improve the electromechanical coupling efficiency of transverse (out-of-plane) vibration. Two optical techniques were employed to investigate the transverse vibration. We first used a non-contact, full-field measurement technique called amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) to determine resonant frequencies and mode shapes in real time. Second, a point-wise measurement device called a laser Doppler vibrometer was used to obtain the spectrum for out-of-plane frequencies. Four electrode configurations with completely free boundary conditions were used to study the electromechanical coupling efficiency of piezoelectric plates. We conclude that the design of the electrodes clearly influences the electromechanical coupling efficiency of piezoelectric plates. The experimental results related to resonant frequency and mode shape were verified using the finite element method (FEM). The numerical calculations are in good agreement with experimental results. Furthermore, according to FEM results, the distribution of electric potential gradient is similar to the mode shape measured by AF-ESPI, making it applicable to the configuration of electrodes in optimizing the excitation of piezoelectric plates. This study proposes the determination of the electromechanical coupling factor to predict the efficiency of transverse vibration in piezoelectric plates.