Scale-Dependent Dynamic-Pull-In of Functionally Graded Carbon Nanotubes Reinforced Nanodevice with Piezoelectric Layer

Abstract

This paper proposes a scale-dependent model to investigate the dynamic-pull-in characteristics of a functionally graded carbon nanotubes (FGCNTs) reinforced nanodevice with a piezoelectric layer. Based on nonlocal beam theory, the nonlinear thermoelectromechanical coupling dynamic governing equation of an electrostatically actuated nanodevice is derived. The material properties of the functionally graded layer depend on temperature environment, thickness, volume ratio, and distribution of carbon nanotubes (CNTs) reinforcement. The van der Waals interaction and Casimir force are considered in the dynamic-pull-in analysis. The homotopy perturbation method is used to obtain a second-order approximated analytical function of nature frequency with respect to initial amplitude. The influences of piezoelectric effect, temperature change, nonlocal parameters, distribution, and volume ratio of CNTs and initial amplitude on dynamic-pull-in behaviors and natural frequencies of the nanodevice are discussed. The results show that the system has one stable focus point at the domain of small initial amplitude and appears in a particular homoclinic orbit originating point and ends at an unstable saddle point.