Thermoelastic Damping in Vibrating Beam Accelerometer: A New Thermoelastic Finite Element Approach

In order to respond to the demand of accurate miniature inertial navigation systems, ONERA has been working on the design of a vibrating beam accelerometer called the Vibrating Inertial Accelerometer (VIA). The accuracy of the VIA is directly related to the thermoelastic quality factor of its sensitive element, which is a beam made of quartz. In this work, thermo-piezoelectric finite element analyses of the beam are carried out in order to determine its thermoelastic quality factor. These finite element results are compared to the analytical and experimental quality factors. Due to their inherent restrictive assumptions, analytical models overestimate the quality factor while the finite element results are in good agreement with the experimental values. As the finite element model allows to take into account the real geometry of the beam and the piezoelectricity of the material, it allows to quantify more precisely the thermoelastic quality factor.