MULTIPHYSIC FEM TOOL FOR CAPACITIVE DIFFERENTIAL PRESSURE SENSORS DESIGN

In this paper a multiphysic Fem model able to design capacitive pressure sensor is presented. The sensor is designed for aerodynamic applications and in particular to operate in the weak pressure field acting on a sail plan. The device is able to detect the differential pressure acting between the leeward and windward side of the sail. The sensing element of the device is a thin conductive diaphragm glue to a PCB structure deflecting under a differential pressure, able to operate in a +/- 250 Pa pressure field. Coupled electrical and mechanical finite element simulations have been performed in order to estimate the sensor behaviour. The Fem multiphysic model developed has been used to predict the behaviour of the sensing element, to achieve the required sensitivity, resolution, and to reduce the drift error due to viscoelastic behaviour of the diaphragm. Viscoelastic effects also heve been taken into account in the simulation process to evaluate the time dependent deformation of the membrane causing a drift of the signal at constant pressure. The Fem model is targeted to supply a powerful tool to design cheap, reliable and conformable pressure devices capable to provide differential pressure maps over full batten sails.