Nonlinear Dynamics of Microelectromechanical Systems

We investigate the dynamic behavior of a micromachined switch including a thin metal membrane called the “bridge”. A nonlinear model is presented considering mechanical force, electrostatic force, and the squeeze-film damping force, and the dynamic equations of a double model for the micromachined system are derived. The numerical simulation of the double model equations indicates that due to nonlinearity in the electrostatic force and the squeeze-film damping force, the micromachined switch undergoes period-doubling and inverse period-doubling bifurcation motion in both the first and second models of the system when the electrostatic excitation is changed. The Poincaré sections show that the period-doubling bifurcation is the typical way to chaos in the system of the micromachined switch. The research shows that nonlinear factors have a very important effect on the dynamic behavior of microelectromechanical systems and even lead to an invalid system.