Thermoelastic coupled modeling for a thermal bimorph actuator

Abstract

This paper presents a theoretical thermoelastic coupled model for a thermal bimorph actuator driven by a harmonically varying thermal load in micro-electro-mechanical systems. The thermoelastic coupling, which arises from the coupling of the strain rate to the temperature field of the heat transport, is considered in this model. The frequency responses are simulated using the theorem of eigenmode expansion. The effects of thermoelastic coupling on the resonant frequency and the quality factor Q for each eigenmode resonance of the deflection are calculated and compared with the same effects resulted from air damping. It shows that for the example of an aluminum-polysilicon thermal bimorph actuator, the resonant frequencies are generally shifted downward with the order larger than that of air damping, whereas the influence of thermoelastic coupling on the Q is more significant than that of air damping under high vacuum level. (c) 2007 Elsevier Ltd. All rights reserved.