Frequency spectra of extensional vibration in Pb(Zr⋅Ti)O3 disks with Poisson’s ratio larger than 1/3

Abstract

The frequency spectra of axially symmetric extensional vibration in piezoelectric Pb(Zr⋅Ti)O3 ceramic disk plates having Poisson’s ratio (σ) of 0.37 have been investigated theoretically and experimentally. The theoretical frequency spectra were calculated with approximation of elastically isotropic disk plates for r (diameter/thickness) of 1 to 30. It was found that the terrace-type spectra which appear in a frequency band between the cutoff frequency of the symmetric thickness-shear mode and the frequency minimum Ω* do not construct a constant frequency bandwidth, in contrast to the case of σ<1/3. Experimental spectra were observed with the Pb(Zr⋅Ti)O3 disk plates for r of 4.8 to 7.2. The experimental spectral agreed well with the theoretical ones, by fitting the cutoff frequency of the fundamental thickness-extensional mode of the elastically isotropic plate to that of the piezoelectric Pb(Zr⋅Ti)O3 ceramic plate. From the results of these analyses, it has been found that the Pb(Zr⋅Ti)O3 ceramic disk plates have resonant vibration responses at or near the cutoff frequency of the symmetric thickness-shear mode, although these vibrations cannot be induced piezoelectrically. Subject Classification: [43]40.24; [43]85.52.