static pull-in analysis of micro beam based on the modified strain gradient theory for different composite materials

In this paper the static pull-in behavior of beam-type micro electromechanical systems (MEMS) made of three different composite material is investigated. based on Euler-Bernoulli beam theory and von-Kármán nonlinear strain assumption, the strain-displacementfield is estimated. The excitation voltage corresponding to the instability is called the static pull-in voltage. The governing static equations are obtained by a combination of the virtual work principle and the modified couple stress theory. It should be noted thatStatic pull-in are calculated using differential quadrature method (DQM). The results of static pull-in voltage is compared with other methods to investigate the accuracy of the present numerical results. Three different composite materials including functionallygraded material (FGM), functionally graded single carbon nanotubes (FG-SCNTs), graphene nanoplatelets (GPLs) are considered. A parametric study is prepared to investigate the effect of Casimir force, Fringing field force, size effect and materials composition on the static pull-in analysis

Keywords:

MEMS , Casimir force , Pull-in voltage , Modified couple stress theory , Fringing field force