Highly Tunable Electrothermally Actuated Arch Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Abdallah Ramini ◽  
Nouha Alcheikh ◽  
Mohammad I. Younis
Keyword(s):  
Resonance Frequency ◽  
Axial Stress ◽  
Beam Theory ◽  
Element Model ◽  
Shallow Arches ◽  
Tunable Resonators ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Euler Bernoulli Beam ◽  
Thermal Voltage

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated MEMS arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and results of a multi-physics finite-element model. A good agreement is found among all the results. The electrothermal voltage is applied between the anchors of the clamped-clamped MEMS arch beam, generating a current that passes through the MEMS arch beam and controls its axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to increase in its curvature, thereby increases the resonance frequencies of the structure. We show here that the first resonance frequency can increase up to twice its initial value. We show also that after some electro-thermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators.

Electrothermally Tunable Bridge Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Nouha Alcheikh ◽  
Abdallah Ramini ◽  
Md Abdullah Al Hafiz ◽  
Mohammad I. Younis
Keyword(s):  
Fundamental Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Bernoulli Beam ◽  
Electrothermal Actuation ◽  
Wide Range ◽  
Simulation Results ◽  
Dc Current ◽  
Euler Bernoulli Beam ◽  
Good Agreement

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

Application of homotopy perturbation method for dynamic analysis of nanotubes delivering nanoparticles

2020 ◽  
pp. 107754632093347
Author(s):  
Beytollah Rezapour ◽  
Mohammad Ali Fariborzi Araghi ◽  
Hector Vázquez-Leal
Keyword(s):  
Perturbation Method ◽  
Homotopy Perturbation Method ◽  
Order Approximation ◽  
Beam Theory ◽  
Nonlinear Frequency ◽  
Inertial Forces ◽  
Homotopy Perturbation ◽  
Vibration Behavior ◽  
Wide Range ◽  
Euler Bernoulli Beam

Because of the importance of the analytical study of the vibration behavior of nanotubes delivering nanoparticles, in this study, the transverse vibration of these systems has been studied by analytical approach based on the homotopy perturbation method. The nonlocal Euler–Bernoulli beam theory is used for derivation of the equation of motion. The interaction between nanoparticle and the inner wall of nanotube has been modeled by using van der Waals forces and considering the effects of inertial forces caused by centrifugal and Coriolis acceleration components of nanoparticles. After evaluation of the implemented analytical method by numerical results, it is revealed that the obtained second-order approximation response gives high accurate vibration behavior of these systems for a wide range of parameters. As well, these results show that inertial forces caused by motion of nanoparticle increase vibration amplitude of nanotube and change nonlinear frequency of the system.

On the forced vibration of carbon nanotubes via a non-local Euler—Bernoulli beam model

2010 ◽  
Vol 224 (2) ◽  
pp. 497-503 ◽  
Author(s):  
P Karaoglu ◽  
M Aydogdu
Keyword(s):  
Carbon Nanotubes ◽  
Forced Vibration ◽  
Beam Theory ◽  
Beam Model ◽  
Bernoulli Beam ◽  
Resonance Frequencies ◽  
Non Local ◽  
Euler Bernoulli Beam ◽  
Bernoulli Beam Model ◽  
Walled Cnts

This article studies the forced vibration of the carbon nanotubes (CNTs) using the local and the non-local Euler—Bernoulli beam theory. Amplitude ratios for the local and the non-local Euler—Bernoulli beam models are given for single- and double-walled CNTs. It is found that the non-local models give higher amplitudes when compared with the local Euler—Bernoulli beam models. The non-local Euler—Bernoulli beam model predicts lower resonance frequencies.

Research and Development of a Rubber O-Ring Sealing Device for High Pressure Vessels

2013 ◽  
Author(s):  
Fan Zhou ◽  
Zhiping Chen ◽  
Haigui Fan
Keyword(s):  
High Pressure ◽  
Pressure Vessel ◽  
Axial Stress ◽  
Element Model ◽  
Pressure Vessels ◽  
Internal Diameter ◽  
High Pressure Vessel ◽  
Threaded Connections ◽  
Wide Range ◽  
Sealing Device

An O-ring made of rubber exhibits excellent sealing performance with a wide range of applications. The highest sealing pressure can be up to 400MPa. The temperature ranges from −60 °C to 200 °C and the medium is low-corrosiveness. This paper proposes an O-ring sealing device for high pressure vessels, which can be opened and operated outside a cylinder. There are no bolts bearing the axial stress under the internal pressure load, and the sealing efficiency of this device is guaranteed by the dimension chain. The whole sealing device has no threaded connections except for the oriented screw which does not bear load under the working conditions. Based on this newly developed sealing device, a high pressure vessel with the design pressure of 60 MPa and the internal diameter of 700 mm used to simulate 6000 m deep sea environment is developed and investigated. This paper firstly introduces the rationale behind the design of the sealing structure for this high pressure vessel, and then discusses a finite element model of the cylinder end for this high pressure vessel and the stress classification method which is used to evaluate the safety of the critical sections. Lastly, the paper presents a set of experimental devices and a series of experiments which were carried out. The results show that the proposed sealing structure can be used in high pressure vessels. The results also verify the assumption of triangle contact pressure distribution between the shear ring and the cylinder end. It is hoped that this study will be of interest and value to researchers when they design the similar structures in the future.

scholarly journals Numerical and Experimental Modeling of Paper-Based Actuators

2021 ◽  
Vol 5 (1) ◽  
pp. 15
Author(s):  
Ashutosh Kumar ◽  
Hojat Heidari-Bafroui ◽  
Amer Charbaji ◽  
Nasim Rahmani ◽  
Constantine Anagnostopoulos ◽  
...  
Keyword(s):  
Beam Theory ◽  
Experimental Modeling ◽  
The Novel ◽  
Cross Sectional ◽  
The Past ◽  
Wide Range ◽  
Loaded Structure ◽  
Electrochemical Phenomena ◽  
And Control ◽  
Euler Bernoulli Beam

Microfluidic paper-based analytical devices (μPADs) have witnessed a great extent of innovation over the past decade, developing new components and materials assisting the diagnosis of different diseases and sensing of a wide range of biological, chemical, optical, and electrochemical phenomena. The novel paper-based cantilever (PBC) actuator is one the major components that allows autonomous loading and control of multiple fluid reagents required for the accurate operation of paper-based microfluidic devices. This paper provides an extensive overview of numerical and experimental modeling of fluidically controlled PBC actuators for automation of the paper-based assay. The PBC model undergoing hygro-expansion utilizes quasi-static 2D fluid loaded structure governed by the Euler–Bernoulli beam theory for small and moderately large deflections. The solution for the model can avail the response of paper-based actuators for response deflection θ, within 0° to 10° under the assumption of insignificant cross-sectional deformation. The actuation of PBC obtained using a quasi-static theory shows that our results are consistent with quantitative experiments demonstrating the adequacy of models.

A Wide Frequency Range Tunable Vibration Energy Harvesting Device Using Magnetically Induced Stiffness

2007 ◽  
Author(s):  
Vinod R. Challa ◽  
M. G. Prasad ◽  
Yong Shi ◽  
Frank Fisher
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Vibration Energy ◽  
Frequency Range ◽  
Vibration Energy Harvesting ◽  
Magnetic Forces ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Continuous Power ◽  
Energy Harvesting Devices

Although wireless sensors show extensive promise across a wide range of applications, one requirement necessary for widespread deployment is a suitable long-life power source. Self sustainable powering techniques allow for efficient use of these sensors, whose potential life is usually longer than that of the power sources. Vibration energy harvesting techniques offer to have the potential to be employed in powering these devices. The most important requirement of vibration energy harvesting devices is that they be in resonance to harvest energy efficiently. Most of the vibration energy harvesting devices built, irrespective of the mechanism involved, are based on a single resonance frequency, with the efficiency of these devices is very much limited to that specific frequency. In this paper, a frequency tunable mechanism is presented which allows the energy harvesting device to generate power over a wide range of frequencies. External magnetic forces have been used to induce additional stiffness which is variable depending on the distance between the magnets. This technique allowed us to tune the resonance frequencies to have +/− 20% of the original (untuned) resonant frequency. Further, the device can be tuned to higher and lower frequency with respect to the untuned resonance frequency by using attractive and repulsive magnetic forces, respectively. As a proof-of-concept, a piezoelectric cantilever-based energy harvesting device with a natural frequency of 26 Hz was fabricated whose resonance frequency was successfully tuned over a frequency range of 22 Hz to 32 Hz, enabling a continuous power output of 240 μW to 280 μW over the entire frequency range. The tuning mechanism can be employed to any vibrating structure.

Dynamic Stress Analysis of Exposed Pipes Subjected to a Moving In-line Inspection Tool

2020 ◽  
pp. 1-35
Author(s):  
Hamid Mostaghimi ◽  
Mohsen Hassani ◽  
Deli Yu ◽  
Ronald J. Hugo ◽  
Simon S. Park
Keyword(s):  
Dynamic Stress ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Assessment Method ◽  
Integrity Assessment ◽  
Defect Assessment ◽  
Pipe Section ◽  
Proposed Model ◽  
Wide Range

Abstract In-line inspection (ILI) is a non-destructive assessment method commonly used for defect assessment and for pipeline monitoring. Passing an ILI tool through an excavated or exposed section of a pipe during an integrity assessment can excite vibrations. The ILI tool's weight and speed can exert substantial forces, stresses, and deflections on the pipe section. When the excitation frequency from the ILI tool's movement is close to the pipe's natural frequency, the dynamic stress generated within the pipe can become great enough that it creates integrity concerns on the pipeline. This research aims to study effects of an ILI tool's passage through exposed and partially supported pipes under a variety of boundary and loading conditions. A finite element model of an exposed pipe section is developed based on the Timoshenko beam theory to predict the pipe's displacement, strain, stress, and frequency responses under a wide range of excitation frequencies. The model is further validated using a lab-scale experimental setup with a mass that moves at different speeds. A comparison between the simulation and the experimental results shows that the proposed model can effectively predict the pipe's dynamics.

scholarly journals On Modeling the Bending Stiffness of Thin Semi-Circular Flexure Hinges for Precision Applications

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 86 ◽  
Author(s):  
Mario Torres Melgarejo ◽  
Maximilian Darnieder ◽  
Sebastian Linß ◽  
Lena Zentner ◽  
Thomas Fröhlich ◽  
...  
Keyword(s):  
Finite Element ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Beam Theory ◽  
Element Model ◽  
Bending Stiffness ◽  
Analytical Models ◽  
Element Analysis ◽  
Flexure Hinges ◽  
Wide Range

Compliant mechanisms based on flexure hinges are widely used in precision engineering applications. Among those are devices such as precision balances and mass comparators with achievable resolutions and uncertainties in the nano-newton range. The exact knowledge of the mechanical properties of notch hinges and their modeling is essential for the design and the goal-oriented adjustment of these devices. It is shown in this article that many analytical equations available in the literature for calculating the bending stiffness of thin semi-circular flexure hinges cause deviations of up to 12% compared to simulation results based on the three-dimensional finite element model for the considered parameter range. A close examination of the stress state within the loaded hinge reveals possible reasons for this deviation. The article explains this phenomenon in detail and shows the limitations of existing analytical models depending on specific geometric ratios. An accurate determination of the bending stiffness of semi-circular flexure hinges in a wide range of geometric parameters without the need for an elaborate finite element analysis is proposed in form of FEM-based correction factors for analytical equations referring to Euler-Bernoulli’s beam theory.

Damping Improvement in Layered and Jointed Beams by Finite Element Analysis

2012 ◽  
Vol 505 ◽  
pp. 501-505 ◽  
Author(s):  
D.N. Thatoi ◽  
R.C. Mohanty ◽  
A.K. Acharya ◽  
B.K. Nanda
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Beam Theory ◽  
Element Model ◽  
Damping Capacity ◽  
Bernoulli Beam ◽  
Element Analysis ◽  
Linear Elastic ◽  
Mass Matrices ◽  
Euler Bernoulli Beam

Damping in built-up structures is produced by the energy dissipation due to micro-slip along the frictional interfaces. A finite element model of the linear elastic system has been formulated using the Euler-Bernoulli beam theory to investigate the damping phenomena in riveted connections. The discrete element system having two degrees of freedom per node representing v and has been used for the analysis. The generalized stiffness and mass matrices for this element has been derived. Extensive experiments have been conducted for the validation of the analysis. From this study, it is established that the damping capacity increases and the natural frequency decreases due to the joint effects.

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