Resonance and antiresonance of symmetric and asymmetriccantilevered piezoelectric flexors

摘要

The resonances of dynamically excited symmetric piezoelectricnbimorphs have been determined from the equations of state. Under theneffect of sinusoidal stimuli: a moment exerted at the tip M, a forcenexerted perpendicular to the plane of the bimorph also applied at thentip F, a uniformly applied pressure p, and an electrode voltage V, theynrespond with a sinusoidal tip rotation Α, tip deflection Δ,nvolume displacement Ν, and electrode charge Q. All of the former arenrelated to all of the latter through a dynamic admittance matrix B. Thenantiresonance frequency of the capacitance C have been found while alsonantiresonance in off-diagonal elements have been determined. The latternindicate that at these frequencies the bimorph does not work as annactuator or sensor in the particular domain of the off-diagonal. Thenmode shape at these antiresonance frequencies has been determined. Thenantiresonance of b14 determines that for this frequency thentip has deflection but no rotation, while the antiresonance of b24n indicates that the tip has rotation but no deflection. Nonantiresonance in the volume displacement is found, indicating that thenbimorph is a pressure converter (microphone) at all frequencies.nMicromachined piezoelectric heterogeneous bimorphs have been fabricatednusing the techniques of I.C. fabrication. Their deflections have beennmeasured as a function of frequency and applied voltage, while thesenhave been compared with the theoretical predictions. An anomalouslynlarge quadratic deflection has been found, superimposed on the linearnpiezoelectric behavior. The agreement between the linear part of thenexperimental deflection and the theory was quite good