An experimental study for characterization of size-dependence in microstructures via electrostatic pull-in instability technique

Abazari, Amir Musa; Fotouhi, Mohammad; Tavakkoli, Hadi; Rezazadeh, Ghader

doi:10.1063/5.0011335

Cited by 13 publications

(7 citation statements)

References 39 publications

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“…Experimental studies and atomistic/molecular dynamic modeling have been carried out by researchers to gain a thorough understanding of mechanical responses of structures at microscale and nanoscale. Due to the small-sized nature of specimens, experimental studies generally require high-precision apparatus and special testing procedure [ 8 ]. However, atomistic/molecular dynamic modeling is a viable method to characterize mechanical responses of micro-sized and nano-sized structures and can provide comprehensive simulation information [ 9 , 10 ] but high computational expense must be paid [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Strain-Gradient Bar-Elastic Substrate Model with Surface-Energy Effect: Virtual-Force Approach

et al. 2022

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This paper presents an alternative approach to formulating a rational bar-elastic substrate model with inclusion of small-scale and surface-energy effects. The thermodynamics-based strain gradient model is utilized to account for the small-scale effect (nonlocality) of the bar-bulk material while the Gurtin–Murdoch surface theory is adopted to capture the surface-energy effect. To consider the bar-surrounding substrate interactive mechanism, the Winkler foundation model is called for. The governing differential compatibility equation as well as the consistent end-boundary compatibility conditions are revealed using the virtual force principle and form the core of the model formulation. Within the framework of the virtual force principle, the axial force field serves as the fundamental solution to the governing differential compatibility equation. The problem of a nanowire embedded in an elastic substrate medium is employed as a numerical example to show the accuracy of the proposed bar-elastic substrate model and advantage over its counterpart displacement model. The influences of material nonlocality on both global and local responses are thoroughly discussed in this example.

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Section: Introductionmentioning

confidence: 99%

Strain-Gradient Bar-Elastic Substrate Model with Surface-Energy Effect: Virtual-Force Approach

et al. 2022

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“…Generally, the most straightforward way to characterize the mechanical properties of structures is the experimental approach. Unfortunately, conducting an experiment on nano-sized structures is extremely cumbersome and requires a high-precision testing apparatus and a unique testing procedure [ 13 , 14 , 15 ]. The atomistic modeling approach based on the quantum mechanics theory could be a viable choice to characterize the mechanical properties of small-sized structures, but high computational costs and complex computational procedures inherently arise with this modeling approach [ 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Static and Free Vibration Analyses of Single-Walled Carbon Nanotube (SWCNT)–Substrate Medium Systems

et al. 2022

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This paper proposes a novel nanobar–substrate medium model for static and free vibration analyses of single-walled carbon nanotube (SWCNT) systems embedded in the elastic substrate medium. The modified strain-gradient elasticity theory is utilized to account for the material small-scale effect, while the Gurtin–Murdoch surface theory is employed to represent the surface energy effect. The Winkler foundation model is assigned to consider the interactive mechanism between the nanobar and its surrounding substrate medium. Hamilton’s principle is used to consistently derive the system governing equation, initial conditions, and classical as well as non-classical boundary conditions. Two numerical simulations are employed to demonstrate the essence of the material small-scale effect, the surface energy effect, and the surrounding substrate medium on static and free vibration responses of single-walled carbon nanotube (SWCNT)–substrate medium systems. The simulation results show that the material small-scale effect, the surface energy effect, and the interaction between the substrate and the structure led to a system-stiffness enhancement both in static and free vibration analyses.

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“…In recent decades, advances in micro electro-mechanical systems (MEMS) including performance enhancement, low power consumption and low fabrication cost have attracted remarkable attention to the use of microdevices in various applications such as micromirrors [1], micro-switches [2], microresonators [3,4], pressure sensors [5], energy harvesters [6,7], gas sensors [8] and capacitive structures [9]. Nevertheless, among various microdevices, capacitive micromachined ultrasonic transducers due to their various benefits including reliable fabrication processes with ease and lower cost, integration with signal processing electronics, efficient performance, low impedance, higher resolution and high transduction coefficient became as an effective technology to overcome many constraints associated with traditional transducers and it can be considered as a primary candidate for next generation of transmitting and receiving ultrasound waves [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…and the upper plate will be compelled to deflect by electrostatic attraction forces, however, the mechanical forces exerted from the movable plate can balance this deflection. An unstable point is where electrostatic force conquer mechanical stiffness of the plate [9,14]. This point is named pull-in.…”

Section: Introductionmentioning

confidence: 99%

Adaptive under-actuated control for capacitive micro-machined ultrasonic transducer based on an accurate nonlinear modeling

et al. 2022

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A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge here is to stabilize the system beyond the pull-in voltage considering imposed perturbations. The CMUT system, on the other hand, has a low range of travel and it is intrinsically unstable, which can result in a pull-in phenomenon. Consequently, in order to use the CMUT systems in a variety of medical applications that require high tuning ratio, a closedloop control technique has been designed for these systems aims at increasing the maximum capacitance and enhancing tunability as well. In this study, using the closed-loop control, the resistance of micro plate against the pull-in phenomenon has been examined. Also, in the description of the system a more accurate nonlinear modeling has been considered in the presence of an under-actuated sliding model control strategy with finite convergence time. Beside, adaptive protocols with unknown upper bounds have been designed to compensate the effects of uncertainty, unmodeled dynamics and external disturbances. The performance of controller in terms of improving output pressure, stabilizing the CMUT and its robustness to imposed perturbations have been investigated. Finally, numerical simulations

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An experimental study for characterization of size-dependence in microstructures via electrostatic pull-in instability technique

Cited by 13 publications

References 39 publications

Strain-Gradient Bar-Elastic Substrate Model with Surface-Energy Effect: Virtual-Force Approach

Strain-Gradient Bar-Elastic Substrate Model with Surface-Energy Effect: Virtual-Force Approach

Static and Free Vibration Analyses of Single-Walled Carbon Nanotube (SWCNT)–Substrate Medium Systems

Adaptive under-actuated control for capacitive micro-machined ultrasonic transducer based on an accurate nonlinear modeling

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