Effects of size-dependent elasticity on stability of nanotweezers

It is well-recognized that the electromechanical response of a nanostructure is affected by its element size. In the present article, the size dependent stability behavior and nanotweezers fabricated from nanowires are investigated by modified couple stress elasticity(MCSE). The governing equation of the nanotweezers is obtained by taking into account the presence of Coulomb and intermolecular attractions. To solve the equation,four techniques, i.e., the modified variational iteration method(MVIM), the monotonic iteration method(MIM), the MAPLE numerical solver, and a lumped model, are used.The variations of the arm displacement of the tweezers versus direct current(DC) voltage are obtained. The instability parameters, i.e., pull-in voltage and deflection of the system,are computed. The results show that size-dependency will affect the stability of the nanotweezers significantly if the diameter of the nanowire is of the order of the length scale. The impact of intermolecular attraction on the size-dependent stability of the system is discussed.