Comparative simulation study of a cylindrical piezoelectric pressure sensor using COMSOL Multiphysics

Abstract

In this work, a two-dimensional (2D) axisymmetric model of a cylindrical piezoelectric pressure sensor was established to exploit its rotational symmetry. Five piezoelectric materials, i.e., PZT-5H, PZT-5A, PVDF, BaTiO3, and AlN, were evaluated to compare their piezoelectric response under internal pressures ranging from 2 to 10 MPa. All five materials show an approximately linear increase in output voltage with increasing pressure. At an internal pressure of 10 MPa, PVDF exhibits the highest output voltage of 262.46 V. This phenomenon is mainly attributed to the dielectric properties of the material. The lower relative permittivity of PVDF leads to a lower equivalent capacitance. For a given amount of generated charge, a smaller capacitance results in a larger potential difference between the electrodes. For the PVDF-based sensor, the inner radius was fixed at 175 μm, and the wall thickness was increased from 50 to 300 μm. As the wall thickness increases, the maximum von Mises stress decreases, while the output voltage increases. From an electrical perspective, increasing the wall thickness enlarges the outer radius, thereby reducing the capacitance. Since the reduction in capacitance exceeds the reduction in mechanical stress, the output voltage increases from 262.64 to 458.83 V. Furthermore, the inverse piezoelectric response of these five materials was investigated. Under a 1 V electrical excitation, PZT-5H produces the largest radial displacement of 1.62 nm, demonstrating its suitability for micro-actuation. This study provides a quantitative basis for material selection and structural optimization of piezoelectric pressure sensors.