EECS500 Fall 2017 Department Colloquium

Hanna Cho, PhD
Exploiting Nonlinearity in MEMS
Ohio State University
White 411
11:30 AM - 12:30 PM
October 3, 2017

Advances in micro/nano-scale fabrication techniques have led the extensive development of MEMS. Many of MEMS employ mechanical elements in micro/nanometer scales, designed to exhibit mechanical motion usually at their resonance frequencies. The high structural quality combined with the reduced effective mass allows such mechanical resonators to operate at very high frequencies and quality-factors, providing the basis for exceptional performance of MEMS/NEMS applications.
The low damping at resonance, however, can elicit large displacements in a mechanical system. At large oscillation amplitudes, nonlinear effects often dominate the global response of a system to exhibit nonlinear hysteresis, multi-stability, or sometimes seemingly unpredictable dynamics. As a result, the linear operational range over which a mechanical resonator remains within the linear regime is reduced significantly to an extremely small magnitude often comparable to the noise level. That’s why there were significant research efforts to restore a linear response by dealing with the increasingly prominent nonlinear effects.
On the other hand, there is a growing interest in exploitation of rich nonlinear dynamic features for use in practical applications of MEMS. Based on the combined experimental and theoretical expertise in both fields of micro/nano-technology and nonlinear dynamics, Dr. Cho’s research has continuously focused on implementing strong intentional nonlinearity in the design of miro/nano-resonators and harnessing its benefits for various applications of micro/nano-systems. This talk will introduce various types of nonlinearity realized in micro/nanomechanical systems and discuss their unique behavioral features that can be exploited in MEMS applications.


Dr. Hanna Cho is Assistant Professor in the Department of Mechanical and Aerospace Engineering at The Ohio State University since 2015. Dr. Cho earned BS and MS degrees in Mechanical Engineering from Yonsei University, South Korea in 2002 and 2004, and a PhD at the University of Illinois at Urbana-Champaign (UIUC) in 2012. Cho’s research laboratory, the Micro/Nano Multiphysical Dynamics Laboratory, is focused on studying nonlinear dynamics in micro/nanomechanical systems to utilize beneficial nonlinear characteristics in developing novel MEMS. She is a Young Faculty Award recipient from Defense Advanced Research Project Agency (DARPA).