Vibration and sensitivity analysis of piezoelectric microcantilever as a self-sensing sensor

Abstract

Piezoelectric microcantilevers (MCs) have extensive applications in microelectromechanical systems. One of the applications of piezoelectric MCs is in self-sensing sensors. These sensors are highly popular due to their high accuracy, quick response, and environmental compatibility. Since the output current of piezoelectric layer is used as the sensing parameter in piezoelectric MCs, sensor optimization requires the maximum output current for each specific vibration. This paper uses dynamic piezoelectric MC analysis in different operating environments (air and liquid) to determine the factors influencing the output current of a piezoelectric layer. To obtain the differential equation of vibration, the hydrodynamic force applied to the piezoelectric MC by using the sphere string model. The equation was obtained via the Euler-Bernoulli beam theory and the Lagrange equation. The differential equation of the movement would yield both the MC deformation and the piezoelectric layer current. Using the Sobol statistical method for sensitivity analysis, the effect of each geometric parameter of the piezoelectric MC on the output current was studied to find the optimal geometry for the maximum output current. Results show that the output power of the piezoelectric layer is reduced in a liquid environment. Moreover, increasing the density of the liquid further exacerbates the drop in the output power. Therefore, in cases where the MC is to be used in a liquid environment (such as in biosensors), it is best to use a low-density liquid. The results also show that the electric current produced in the piezoelectric layer increases by reducing the length of the MC.