Size-Dependent Dynamic Behavior and Instability Analysis of Nano-Scale Rotational Varactor in the Presence of Casimir Attraction
Size-Dependent Dynamic Behavior and Instability Analysis of Nano-Scale Rotational Varactor in the Presence of Casimir Attraction
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DOI：
10.1142/s1758825116500186
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发表时间：
2016-04
影响因子：
3.5
通讯作者：
H. M. Sedighi;M. Moory-Shirbani;M. Shishesaz;A. Koochi;M. Abadyan
中科院分区：
文献类型：
--
作者：
H. M. Sedighi;M. Moory-Shirbani;M. Shishesaz;A. Koochi;M. Abadyan
当结构的尺寸接近亚微米尺度时，这类系统的物理响应变得依赖于尺寸，因此，经典理论可能无法预测微型结构的行为。在本文中，修正的偶应力理论（MCST）的扭转纳米机电系统（NEMS）变容管的动态不稳定性的尺寸依赖性的效果。通过引入库仑力、Casimir力和阻尼力，推导了无量纲的控制方程.通过绘制相图和分岔图，研究了Casimir力、外加电压和长度尺度参数对不动点动力学行为和稳定性的影响。结果表明，Casimir力降低了系统的失稳阈值，小尺度参数增强了系统的扭转稳定性。扭转型纳米变容管的吸合失稳现象表现为鞍结分岔。
When the size of structures approaches to the sub-micron scale, physical responses of such systems become size-dependent, hence, classic theories may not be able to predict the behavior of the miniature structures. In the present article, the modified couple stress theory (MCST) is employed to account for the effect of the size-dependency on the dynamic instability of torsional nano-electromechanical systems (NEMS) varactor. By incorporating the Coulomb, Casimir and damping forces, the dimensionless governing equations are derived. The influences of Casimir force, applied voltage and length scale parameter on the dynamic behavior and stability of fixed points are investigated by plotting the phase portrait and bifurcation diagrams. It is found that the Casimir force reduces the instability threshold of the systems and the small-scale parameter enhances the torsional stability. The pull-in instability phenomenon shows the saddle-node bifurcation for torsional nano-varactor.