Torsional Sensors for Conical Shell in Torsional Vibrations

This paper presents shear piezoelectric sensors for conical shell sensing. The piezoelectric patch is polarized in the longitudinal direction of conical shell structure. The electrodes are fixed at the sides parallel to the directions of polarization. Sensors in this arrangement are only sensitive to the in-plane shear strains. Both sensing equations and modal signals are derived based on the thin-shell assumption and piezoelectric effect. Numerical results are presented for free torsional vibrations of frustum shell of revolution with clamped-free boundary, and the effects of sensor length on the output are evaluated. The amplitudes of the output signal of the sensors are lower than that of modal ones, but they are all share the same trends. The amplitudes depend on the deformation of the shell and the length of the sensor. The results indicate the optimal locations of the piezoelectric sensor for sensing the torsional vibration of clamped-free shell. The output signals of the sensor can be used as the control input for later active vibration control. The sensing equations are applicable to sense shear strains and torsion of other type shells by replacing the strain equation.