Effect of Boundary Form Disturbances on the Frequency Response of Planar Vibrations of Piezoceramic Plates. Experimental Investigation

Abstract

Experimental results for forced planar vibrations of parallelogram-shaped piezoceramic plates are presented. The concept of this study is to evaluate the potentials of controlling the spectrum of natural frequencies and electromechanical coupling coefficients of plates by changing their shape. The results permit of supporting the data on analytical and numerical investigations of dynamics of piezoceramic plates and establishing the consistency between the physical properties of a real plate and the assumptions of the ideal computational model in the solution of practical problems. Comparison of calculated and experimental data for the spectrum of natural frequencies of the plate over their rather wide range can demonstrate this consistency. The experimental procedure was tested in studying the vibration behavior of SM111 ceramic square and parallelogram-shaped plates with different side slopes. The frequency range of investigations is limited from above with 140 kHz, which provides effective excitation of a sufficient number of natural vibrations. The structure of an experimental complex and excitation mode of vibrations at actual values of the quality factor permit of considering the external voltage source as the infinite power one. The excitation of asymmetric vibration modes on the change in geometry of a rectangular plate is natural. As was shown, high-order modes (very low electromechanical coupling coefficients in rectangular plates) can be effectively excited in parallelogram-shaped plates with maintaining a uniform electrode coating. It needs the traditional estimates of electromechanical coupling coefficients in piezoelectric plates to be refined with regard to inhomogeneous stress and strain fields.