An Investigation of the Effects of Crack on the Zone of Pull-in Suppression in Micro-Electromechanical Systems Using High-Frequency Excitation

In this paper, the pull-in phenomenon is suppressed using a range of values of amplitude and frequency of high-frequency voltage excitations in the post pull-in condition of the cracked microelectromechanical systems. These specified ranges are named as stable zones. It is investigated the effects of the crack parameters (depth and location) on changes of these zones, in the post pull-in condition. It is shown that these zones have different areas for different crack parameters. The cracked micro-beam is modeled as a single-degree-of-freedom systems consist of mass-spring-damper and the motion equation of the cracked micro-beam is extracted. The method of direct partition of motion is used to split the fast and slow dynamics. By means of slow dynamic part, the effects of the crack on the averaged position of vibration of cracked micro-beam are investigated versus voltage amplitude and frequency of the highfrequency AC. By approaching the crack to the fixed end or increasing the depth of crack, the stability zone reduced. Therefore, the pull-in instability can be suppressed in the lower range of amplitude and frequency. This method can be used in sensors’ health-monitoring and one can predict the parameters of the crack using this method.