Large Deformation and Vibration Analysis of Microbeams by Absolute Nodal Coordinate Formulation

This investigation uses the absolute nodal coordinate formulation (ANCF) method to solve statics and dynamics of microbeams for the first time. A comprehensive model for the investigation of statics and dynamics of microbeams by using gradient deficient elements of the ANCF and modified couple stress theory (MCST) is developed. The vibration equations of a planar hub-microbeam system with constant angular rotations are derived considering the static equilibrium. Accuracy of the ANCF method for microbeams is demonstrated. Large deformation problems of cantilever microbeams are solved and the influences of material length scale on beam deformation are studied. When the beam thickness becomes smaller, the deflection of the microbeam calculated by the current model is smaller, and the size effect becomes more significant. The size effect only has influence on the bending vibration of the microbeam. The variations of the angular speed as well as the scale parameter can trigger frequency veering phenomena. The present work could be used in dynamic or vibration predictions for microelectromechanical systems (MEMS) with both large displacements and large deformations.