Modeling the pull-in instability of the CNT-based probe/actuator under the Coulomb force and the van der Waals attraction

Carbon nano-tube (CNT) is applied to fabricate nano-probes, nano-switches, nano-sensors and nano- actuators. In this paper, a continuum model is employed to obtain the nonlinear constitutive equation and pull-in instability of CNT-based probe/actuators, which includes the effect of electrostatic interaction and intermolecular van der Waals (vdW) forces. The modified Adomian decomposition (MAD) method is applied to solve the nonlinear governing equation of the CNT-based actuator. Furthermore a simple and useful lumped parameter model was developed to investigate trends for various pull-in parameters. The influence of the vdW force and the geometrical dimensionless parameter on the pull-in deflection and voltage of the system is investigated. The obtained results are compared with those available in the literature as well as numerical solutions. The results demonstrate that our developed continuum based model is in good agreement with experimental results