An analytical model for the thermoelastic actuation of composite diaphragms

An analytical model for the thermoelastic actuation of a circular composite diaphragm is presented. The model incorporates several key aspects relevant to micromachined thermoelastic resonators including multiple material layers, in-plane heat conduction and fabrication-induced stresses. Using a Fourier heat conduction model, expressions for the 2-D temperature distribution in the composite diaphragm generated by the dynamic Joule heating of diffused resistors are obtained via Hankel transforms and Green´s functions. The thermoelastically forced vibration of the composite diaphragm is analyzed using classical Kirchoff plate theory and solved to obtain expressions for the transverse diaphragm deflection. Comparisons of the analytical model with coupled thermal-mechanical finite element simulations show excellent agreement with significantly faster (80/spl times/) computation time.