Loading...

Nonlinear Vibration and Pull-in Analysis in Electrostatically Actuated Nano/Micromirrors

Moeenfard, Hamid | 2012

911 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 43745 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Ahmadian, Mohammad Taghi
  7. Abstract:
  8. The important role of MEMS devices in optical systems has initiated the development of a new class of MEMS called Micro-Opto-Electro-Mechanical Systems (MOEMS), which mainly includes nano/micromirrors and torsional nano/microactuators. These devices have found variety of applications in optical switches, displays, micro scanning mirrors, optical cross-connects, interferometery, spectroscopy, aberration correction and biomedical imaging. In this project, the static and dynamic behavior of electrostatic nano/micromirrors under the effect of intermolecular surface forces and squeezed film damping are studied. The prior art published in the literature have mainly used pure torsion models. In a pure torsion model, just the torsion of the supporting beams are considered in the formulations,while in practical situations, in addition to torsion, bending of the supporting beams come into play as well. In order to overcome these limitations, in this project a coupled two degree of freedom torsion-bending model has been used for modeling the nano/micromirror's behavior. The minimum total potential energy principal is used to model and the straight forward perturbation expansion is used to solve the problem of static behavior of the nano/micromirrors. Implicit function theorem is then utilized to predict the pull-in angle and pull-in deflection of the mirror. The problem of squeeze film damping in micromirrors is also solved considering both torsion and bending of the supporting beams using extended Kantorovich method as well as the method of separation of variables. Analytical nonlinear expressions are suggested for the damping force and damping torque applied to the mirror. Finally the nonlinear vibrational behavior of the mirror is modeled using the Lagrange equations and primary and secondary resonances are analyzed using themultiple time scale perturbation method. The results reveal that the pure torsion model is incapable of accurate modeling of the mirror's vibrational behavior
  9. Keywords:
  10. Electrostatic Actuation ; Pull-in Phenomenon ; Nonlinear Vibration ; Squeeze Film Damping ; Extended Kantorovich Method ; Nanomicro Mirror ; Intermolecular Surface Force

 Digital Object List

 Bookmark

...see more