Thermoelastic damping in nanomechanical resonators with finite wave speeds

The operation of micro-/nanobeams vibrating at very high frequencies, such as encountered in micro-/nanoelectromechanical systems (MEMS/NEMS), hinges on the minimization of intrinsic material losses. We study the associated thermoelastic damping in such beams from the standpoint of a generalized theory of thermoelasticity with one relaxation time. Some of our results relate to: (i) the cooling ( instead of heating) in the compressed surface of the beam; (ii) the existence of not one damping peak appearing in the classical theory, but many peaks, with a decreasing amplitude as the frequency tends to infinity; (iii) the relevance of thermoelasticity with finite wave speeds for frequencies on the order of 10(12) Hz.