scholarly journals Pull-In and Snap-Through Analysis of Electrically Actuated Viscoelastic Curved Microbeam

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Ehsan Akrami-Nia ◽  
Hamid Ekhteraei-Toussi
Keyword(s):  
Governing Equation ◽  
Couple Stress Theory ◽  
Viscoelastic Behavior ◽  
Modified Couple Stress Theory ◽  
Stress Theory ◽  
Viscoelastic Parameters ◽  
Relaxation Coefficient ◽  
Electromechanical Instability ◽  
Curved Microbeam ◽  
Viscoelastic Microbeam

Microbeams are key elements in most of the micro-electromechanical systems (MEMS). Electromechanical instability of microbeams in turn plays an important role in their applications. The shape and mechanical properties of microbeams dictate their functional characteristics. Focusing on their instability-based working mechanism, one can appreciate that viscoelasticity of MEMS materials cannot be neglected. Consequently, the analysis of instability in viscoelastic curved microbeams is an essential demand. In this research, assuming a clamped-clamped initially curved microbeam, the effects of viscoelastic behavior on the snap-through and pull-in instabilities are investigated. The standard inelastic linear solid model is used for the simulation of viscoelastic behavior. Integrodifferential governing equation of the curved viscoelastic microbeam is obtained by assuming modified couple stress theory and using Hamilton’s principle. By applying the Galerkin method, the obtained governing equation is discretized, converted to a nonlinear differential equation, and solved by MATLAB software. Through a quasi-static analysis, the voltage and location of snap-through and pull-in instabilities are identified. The effects of different viscoelastic parameters including the creep moduli and relaxation coefficient upon the snap-through and pull-in instabilities are investigated. The effects of different short- and long-term creeping characteristics of viscoelastic microbeam are studied and discussed in detail.

Influence of Accelerating Force on the Electromechanical Instability of Paddle-Type and Double-Sided Sensors Made of Nanowires

2016 ◽  
Vol 08 (01) ◽  
pp. 1650011 ◽  
Author(s):  
Maryam Keivani ◽  
Abolfazl Kanani ◽  
Mohammad Reza Mardaneh ◽  
Javad Mokhtari ◽  
Naeimeh Abadyan ◽  
...  
Keyword(s):  
Couple Stress Theory ◽  
Variational Iteration Method ◽  
Modified Couple Stress Theory ◽  
Geometrical Parameters ◽  
Stress Theory ◽  
Electromechanical Instability ◽  
Modified Couple Stress ◽  
Proximity Force Approximation ◽  
Casimir Attraction ◽  
The Impact

The double-sided and paddle-type nanostructures are promising for developing miniature accelerometers. In the present work, the impact of the accelerating force on the pull-in performance of the double-sided and paddle-type sensors fabricated from nanowire are investigated. The proximity force approximation (PFA) is employed to consider the effect of Casimir attraction in the theoretical model. Using the modified couple stress theory, the constitutive equations of the sensors are derived. The governing equations are solved by two different approaches, i.e. modified variational iteration method (MVIM), and finite difference method (FDM). The influences of the Casimir and accelerating forces, geometrical parameters and the size phenomenon on the pull-in parameters are demonstrated.

scholarly journals Snap-through buckling of initially curved microbeam subject to an electrostatic force

2015 ◽  
Vol 471 (2177) ◽  
pp. 20150072 ◽  
Author(s):  
X. Chen ◽  
S. A. Meguid
Keyword(s):  
Electrostatic Force ◽  
Couple Stress Theory ◽  
Beam Theory ◽  
Intermolecular Forces ◽  
Modified Couple Stress Theory ◽  
Casimir Forces ◽  
Governing Equations ◽  
Stress Theory ◽  
Fringing Field ◽  
Curved Microbeam

In this paper, the snap-through buckling of an initially curved microbeam subject to an electrostatic force, accounting for fringing field effect, is investigated. The general governing equations of the curved microbeam are developed using Euler–Bernoulli beam theory and used to develop a new criterion for the snap-through buckling of that beam. The size effect of the microbeam is accounted for using the modified couple stress theory, and intermolecular effects, such as van der Waals and Casimir forces, are also included in our snap-through formulations. The snap-through governing equations are solved using Galerkin decomposition of the deflection. The results of our work enable us to carefully characterize the snap-through behaviour of the initially curved microbeam. They further reveal the significant effect of the beam size, and to a much lesser extent, the effect of fringing field and intermolecular forces, upon the snap-through criterion for the curved beam.

A corrected model for static and dynamic electromechanical instability of narrow nanotweezers: Incorporation of size effect, surface layer and finite dimensions

2018 ◽  
Vol 32 (08) ◽  
pp. 1850089 ◽  
Author(s):  
Ali Koochi ◽  
Hossein Hosseini-Toudeshky ◽  
Mohamadreza Abadyan
Keyword(s):  
Coupling Effect ◽  
Couple Stress Theory ◽  
Surface Elasticity ◽  
Modified Couple Stress Theory ◽  
Stress Theory ◽  
Electromechanical Instability ◽  
Narrow Width ◽  
Casimir Attraction ◽  
Vdw Force ◽  
The Impact

Herein, a corrected theoretical model is proposed for modeling the static and dynamic behavior of electrostatically actuated narrow-width nanotweezers considering the correction due to finite dimensions, size dependency and surface energy. The Gurtin–Murdoch surface elasticity in conjunction with the modified couple stress theory is employed to consider the coupling effect of surface stresses and size phenomenon. In addition, the model accounts for the external force corrections by incorporating the impact of narrow width on the distribution of Casimir attraction, van der Waals (vdW) force and the fringing field effect. The proposed model is beneficial for the precise modeling of the narrow nanotweezers in nano-scale.

Sign in / Sign up

Export Citation Format

Share Document