Finite element modeling of thermoelastic damping in filleted micro-beams

In the design of micro-electromechanical systems, which require a high quality factor, the dissipation mechanisms such as the thermoelastic damping have to be considered. In order to assess the thermoelastic influence on the behavior of vibrating structures, analytical mod-els may be used for simple configurations under very restrictive assumptions. In order to study more complex structures, the finite element method may be used. Two simple cases for which analytical models exist are investigated in this paper. An oscillating clamped-clamped beam and a vibrating bar are modelled using thermoelastic finite elements. The analytical and finite element analyses show that the thermoelastic coupling implies a nat-ural frequency shift, an amplitude attenuation, a difference of phase between the thermal and mechanical degrees of freedom and influences the quality factor of the resonating system. Keywords: Finite elements, thermoelastic coupling, thermoelastic damping, micro-structures