Volume 15, Issue 2 (4-2015)                   Modares Mechanical Engineering 2015, 15(2): 101-112 | Back to browse issues page

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Karimipour I, Karimipour A R, Tadi Beni Y. Determination of size-dependent non-linear pull-in instability of clamped nano-Beam based on the modified strain gradient theory using HPM. Modares Mechanical Engineering 2015; 15 (2) :101-112
URL: http://mme.modares.ac.ir/article-15-11411-en.html
Abstract:   (5309 Views)
In recent decade, modeling the instability of nanostructures has attracted many attentions in nanomechanics. Nanomechanical switches are fundamental building blocks for the design of NEMS applications, such as nanotweezers and nanoscale actuators. One common type of NEMS including nano-bridge in micro mirrors is used. At nano-scales, the decreasing gap between the two electrodes makes surface traction due to molecular interaction such as van der Waals that must be taken into account in the analysis of NEMS. In this study, strain gradient theory has been used to investigate the size dependent pull-in instability of beam-type (NEMS)where is an inherent instability in them. The von-Karman nonlinear strain has been applied to derive the constitutive equation of the system. Effect of intermolecular force have been included in the nonlinear governing equations of the systems. Homotopy perturbation method (HPM) has been employed to solve the nonlinear equations. Effect of intermolecular attraction and the size dependency and the importance of coupling between them on the instability performance i.e. critical deflection and instability voltage have been discussed. According the findings of this research, one can conclude that intermolecular forces decrease pull-in voltage and size effect parameter in nano scale leads to increase of pull-in parameters. Also HPM method can be applied as efficient method to analyze beam type nano structures.
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Article Type: Research Article | Subject: Micro & Nano Systems
Received: 2014/09/21 | Accepted: 2014/10/30 | Published: 2014/12/24

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