Authors: D.N. Pawaskar and R. Phillips
Affilation: California Institute of Technology, United States
Pages: 364 - 367
Keywords: energy dissipation, vibration, beam, quality factor, dislocations, grain boundaries
Mechanical damping strongly influences the sensitivity and resolution of nano-sensors and actuators. In this paper, we have investigated one of the key intrinsic mechanisms responsible for dissipation of vibrational energy in beams composed of a polycrystalline material, namely motion of grain boundaries. The focus has been on modeling the movement of the grain boundary perpendicular to the interfacial plane. To this end, we have modeled the interface as an array of dislocations. By accounting for all forces acting on individual dislocations, we are able to extract the effective motion of the interface and thus compute cyclical energy losses. We have predicted the dependence of the mechanical quality factor (Q) on the grain boundary misorientation and inclination angles, and proposed an experiment based on our results.