Coupling effect of surface energy and dispersion forces on nonlinear size-dependent pull-in instability of functionally graded micro-/nanoswitches

摘要: In this paper, an integrated nonclassical multi-physics model is developed to study the coupling effect of surface energy and local microstructure on nonlinear size-dependent pull-in instability electrostatically actuated functionally graded material (FGM) micro-/nanoswitches. The incorporates influences fringing field, dispersion Casimir or van der Waals force in addition residual axial stress mid-plane stretching. For more accurate analysis FGM switches, a beam based Euler–Bernoulli theory conjunction with modified couple Gurtin–Murdoch elasticity account for size dependency effects, respectively. Material properties both bulk layers switch are assumed vary according power law distribution through thickness. To end, Hamilton principle employed derive governing integral–differential equations associated boundary conditions, without neglecting any terms raised by energy. relations derived general form, which can be reduced those different theories, including theory, classical theories. resulting solved utilizing generalized differential/integral quadrature method, conditions exactly implemented immovable ends. obtained results compared available literature valid efficiency present solution method. A numerical reveals that voltage micro-/nanoswitches significantly influenced FGM’s gradient index, length scale parameter, energy, stress, initial gap, slenderness ratio, forces conditions.