Investigation of the torsional effect of a piezoelectric quartz disc and torsion chargesensitivity

Abstract

The torsional effect of a piezoelectric quartz disc and the distribution of torsion chargesensitivity are first investigated in this paper. The torsion stresses of a circular quartz discare deduced by using the theory of anisotropic elasticity, and then through the Maxwellelectromagnetic theory and piezoelectricity the distribution of bound volume and surfacecharge densities is computed. In order to make use of the torsional effect of a quartzdisc and reduce the cross talk, the distribution of torsion charge sensitivity isinvestigated theoretically by means of coordination transformation and verifiedexperimentally. Based on theoretical analyses of the bound charge densities andtorsion charge sensitivity, the detection electrodes are effectively arranged on thesurface of the piezoelectric disc. The theoretical and experimental results show thatthe charge measured is linear with the torque applied and the torsion quartzmeasuring cell is only sensitive to torque that is independent of axial and radialforce.