Improving the sensitivity of piezoelectric excited millimeter-sized cantilevers in sensing applications

Abstract

In this study, performance of piezoelectric excited millimeter-sized cantilever (PEMC) beams has been studied in applications such as mass and liquid level sensor using finite element analysis. For this purpose, a finite element model is developed and the simulation results are compared with experimental results in order to validate the proposed model. After validation of the proposed model, this model is used to explore the effects of distribution of added mass along beam's length and its pattern and also effect of variation in beams cross section profile on sensor sensitivity. While previous works are focused on conditions in which added mass is coated at the tip of the beam with constant rectangular cross section, in present study uniform and Gaussian distributions of coated mass in different regions of beam are examined. Also, PEMC with a non-uniform beam cross section (trapezoidal shape) as mass sensor is modeled and the improvement of sensor performance has been examined. The results show that both pattern of coated mass distribution and the regions in which the mass is coated have massive effect on performance of sensor. Moreover, the present results indicate that trapezoidal shape sensors are more sensitive comparing to more conventional rectangular ones. In order to extend this work for other sensing applications of PEMC, liquid level detection sensors with trapezoidal shape beam are modeled and studied. The related results indicate that a higher sensitivity can be achieved for this type of sensors using trapezoidal shape beam too.