THE INFLUENCE OF SMALL SCALE ON THE PULL-IN BEHAVIOR OF NONLOCAL NANOBRIDGES CONSIDERING SURFACE EFFECT, CASIMIR AND VAN DER WAALS ATTRACTIONS

This paper is proposed to study the dynamic pull-in instability of nonlocal nanobridges incorporating the surface effect and intermolecular forces. The second-order frequency-amplitude relation is introduced via an asymptotic approach namely homotopy perturbation method (HPM). The effects of applied voltage and intermolecular parameters on pull-in instability as well as the natural frequency are investigated. Furthermore, the influence of nonlocal parameter and surface energy on the dynamic pull-in voltage is considered. It is shown that two terms in series expansions are sufficient to produce an acceptable solution of the mentioned nanostructure. The obtained results from numerical methods verify the strength of the analytical procedure. The qualitative analysis of the system dynamic shows that the equilibrium points of the autonomous system include center points with periodic trajectories and unstable saddle points with homoclinic orbits.