Theoretical study of the effect of Casimir force, elastic boundary conditions and size dependency on the pull-in instability of beam-type NEMS

In this paper, the static pull-in instability of beam-type nano-electromechanical systems (NEMS) is theoretically investigated considering the effect of Casimir attraction, elastic boundary conditions (BC) and size dependency. Rotational springs are utilized at each of the supported ends of the simply and doubly supported beams to model an elastic BC. The modified couple stress theory is applied to examine the size effects on the instability of nanostructures. In order to solve the nonlinear constitutive equation of nano-beams, modified Adomian decomposition (MAD) as well as the numerical method is employed. The results reveal significant influences of Casimir attraction, elastic BC and size dependency on the pull-in characteristics of NEMS. The obtained MAD solution agrees well with the numerical one.