Enlarging quality factor in microbeam resonators by topology optimization

Abstract

The fundamental characteristic of mechanical resonators can be evaluated by resonance eigenfrequency and energy dissipation (or inverse quality factor). Reduced length scales are necessary for achieving high resonance eigenfrequency, which can afford fast response and extraordinary sensitivity to external forces. However, smaller scales will result in higher energy dissipation (or smaller quality factor) in the eigenfrequency of mechanical resonators. A topology optimization process is presented for enlarging quality factor of a microbeam resonator made of linear, isotropic and homogeneous thermoelastic material. The beam’s width is supposed to be considerable so that the plane strain assumption can be satisfied and the design domain is the cross section along the beam’s thickness. By combining the equation of motion and the heat transfer equation, the damping problem of thermoelastic coupling can be solved by a finite-element method. A topology optimization method is used to enlarge quality factor in microbeam resonators. It is found by clamped-clamped and clamped-free microbeam resonators that significant improvements of quality factors can be achieved through this optimization process.