Nonlinear dynamics of micro impact oscillators in high frequency MEMS switch application

In this paper, we propose a piecewise nonlinear model for the first time to understand the impact dynamics of micro-oscillator applications including MEMS switches and tapping-mode atomic-force-microscopy (AFM). Specifically, we consider the case when the deformation is large and the tapping happens in the nonlinear frequency response region. In-plane switches and cantilevers with out-of-plane motion, made from single crystal silicon with simple geometry are used for modeling and testing. Both softening and hardening effects are considered. A laser-scanning-vibrometer system is used for quantifying motion. Numerical analysis shows that the nonlinearity not only shifts the bifurcation area, but also changes the bandwidth of the tapping event. The comparison between the experimental results and the simulation results demonstrates the validity of the piecewise nonlinear model we propose.