Axial prestress is built into those micromechanical beam resonators made of deposited thin films. This prestressaffects elastic strain distribution in a beam resonator and thus has the potential of changing its thermoelastic damping (TED). In this paper, a theoretical model of TED in a micromechanical beam resonator with axial prestressis developed to study the effect of axial prestress on TED in such resonators. This theoretical model is built upon a thermal-energy method and therefore TED is calculated as the generated thermal energy during one cycle of vibration. An explicit expression for the Qted, the Quality factor due to TED, is obtained from this developed model. As a result, this work suggests that, for a beam resonator with axial prestress.its Q_(TED) increases with tensile prestressand decreases with compressive prestress.
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