EFFECT OF BOUNDARY FORM DISTURBANCES ON THE FREQUENCY RESPONSE OF PLANAR VIBRATIONS OF PIEZOCERAMIC PLATES. EXPERIMENTAL INVESTIGATION

  • By Ken Keith
  • 12 months ago
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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.