Article ID Journal Published Year Pages File Type
785905 International Journal of Mechanical Sciences 2012 12 Pages PDF
Abstract

In spite of practical relevance, little effort has been made to analyze the effect of geometrical shape of cross-section on thermoelastic dissipation of micro/nano beams under different surface thermal condition. The present paper aims to study thermoelastic dissipation of micro/nano beams of elliptical, triangular or arbitrary rectangular cross-section with accurate satisfaction of the surface thermal condition. Detailed formulas are derived for quality (Q-) factor of beams of the above-mentioned cross-sections. Our results show that for all cross-section discussed, thermoelastic dissipation is a non-monotonic function of the absolute size of the cross-section provided the beam length is fixed, and the maximum dissipation appears at a specific size which is of the order of a few hundreds of nanometers for examples discussed. These results suggest that thermoelastic dissipation could increase with decreasing cross-sectional size within the micron scale, while it could decrease with decreasing cross-sectional size within the nano scale. In general, for all beams of the above-mentioned cross-sections, the Q-factor for isothermal surface is always higher than the Q-factor for adiabatic surface under otherwise identical conditions at micro/nano scales. The present analysis also indicates that, to achieve a high quality factor, beam resonators with elliptical or triangular cross-sections are best to operate at higher frequencies while beams of rectangular cross-sections are best to operate at lower frequencies.

► We have studied effects of shape of cross-section on thermoelastic dissipation. ► We have considered arbitrary rectangular, elliptical and triangular cross-sections. ► Both adiabatic and isothermal surface conditions are studied. ► Elliptical and triangular can be superior than rectangular cross-section.

Related Topics
Physical Sciences and Engineering Engineering Mechanical Engineering
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