Computational Simulation for Square Diaphragms of a Piezoresistive Pressure Sensor

This paper presents a methodology for analytical computation and computational simulation using the finite element method - FEM for a piezoresistive sensor element in flexible polymer substrate A4 paper type. The computational simulation aims to find the region of greatest mechanical stress of the clamped square diaphragm set in the four sides, when a pressure is applied. The steps for the simulation are the definition of the geometry, generation of the mesh, inclusion of the properties of the material and execution of the simulation. The mathematical modeling of maximum mechanical stress is described analytically and computationally using ANSYS software. The analytical calculations were compared with the computational simulation and presented a relative percentage error of 13.61% for the maximum mechanical stress. In this work, it is verified that the piezoresistor should be positioned in the middle of the diaphragm edges a / b = 1 to take advantage of the maximum mechanical stress curves. The result is extremely important and will define the best location for deposition of graphite films in future fabrications of sensor elements.