Size effect on performance of Resonant Piezoelectric Millimeter-sized Cantilevers using as liquid level detection sensors

Resonant Piezoelectric-excited Millimeter-sized Cantilevers (PEMC), has attracted many researchers´ interest in the applications such as liquid level and density sensing. As in these applications, the PEMC are partially immersed in liquid, an appropriate analytical model is needed to predict the dynamic behavior of these devices. In this work, a PEMC has been fabricated for liquid level sensing. Analytical model based on Euler-Bernoulli beam theory is developed and applied to evaluate the dynamic behavior of this device in different tip immersion depths. To validate the proposed model, the theoretical results are compared with experimental results for the tip immersion depths from 5 mm to 15 mm in water. The simulation results are in almost good agreement with experimental data. After the validation of the theoretical model, to examine the performance of the PEMC as a liquid level sensor, the effect of geometrical dimensional and resonant mode changes on PEMC performance parameters such as sensitivity and working range is investigated for different mode shapes of PEMC vibration. A liquid level change of about 8μm could be detected by the proposed design (2^nd design) in 5^th resonant mode.