Free vibration of a silicon microbeam in micro-electromechanical systems (MEMS) subjected to electrostatic and axial forces is studied in the framework of a sinusoidal shear deformation theory. A nonlinear finite element formulation based on the von Kármán nonlinear assumption and the modified couple stress theory (MCST) is formulated and employed to establish the discrete nonlinear governing equations for the microbeam. |