scholarly journals Nonlinear dynamics of mode-localized MEMS accelerometer with two electrostatically coupled microbeam sensing elements

2021 ◽  
Vol 8 (2) ◽  
pp. 233-246
Author(s):  
Nikita F. Morozov ◽  
◽  
Dmitriy A. Indeitsev ◽  
Vasilisa S. Igumnova ◽  
Alexei V. Lukin ◽  
...  
Keyword(s):  
Longitudinal Direction ◽  
Dynamic Mode ◽  
Amplitude Ratios ◽  
Nonlinear Dynamic Model ◽  
Mems Accelerometer ◽  
Beam Elements ◽  
Mode Of Operation ◽  
Acceleration Vector ◽  
Fixed Electrode ◽  
Electrostatic Coupling

In the presented work, a model of a microelectromechanical accelerometer with two movable beam elements located between two fixed electrodes is proposed. The action of the transfer forces of inertia in the longitudinal direction leads to a change in the spectral properties of the system, which is a useful output signal of the sensor. The dynamics of the system in the presence of a weak electrostatic coupling between the sensitive elements is characterized by the phenomenon of modal localization - a significant change in the amplitude ratios for the forms of inphase and antiphase oscillations with small changes in the measured component of the acceleration vector of the moving object. Diagrams of equilibrium positions are plotted for varying the potential difference between a fixed electrode and a movable element and between two movable elements. The dependences of the frequencies and the ratio of the components of the eigenvectors on the magnitude of the inertial action are investigated. It is shown that the sensitivity of a sensor based on modal localization can be orders of magnitude higher than the sensitivity of known systems based on measuring the shift of natural frequencies. A nonlinear dynamic model of an accelerometer with external harmonic electrostatic excitation of oscillations is constructed. Resonance characteristics are obtained, a comparison is made between the model describing the modal characteristics of the system and the model describing the real dynamic mode of operation taking into account nonlinear factors.

scholarly journals Rotating Disk Apparatus: Types, Developments and Future Applications

2016 ◽  
Vol 10 (8) ◽  
pp. 198 ◽  
Author(s):  
Musaab K. Rashed ◽  
Hayder A. Abdulbari ◽  
Mohamad Amran Mohd Salleh ◽  
M. Halim Shah Ismail
Keyword(s):  
Reaction Rate ◽  
Rotating Disk ◽  
Rotating Disk Electrode ◽  
Solid Surfaces ◽  
Dynamic Mode ◽  
Power Losses ◽  
The Past ◽  
Consumption Reduction ◽  
Mode Of Operation ◽  
Mode Of Transportation

Power consumption reduction investigations attracted the attention of enormous numbers of researchers in the past few decades due to its high academic and economic impacts. The pumping power losses during the transportation of crude oils are considered as one of the main power consuming applications due to the turbulent mode of transportation. Investigating the possible solutions for this problem is expensive and time consuming due to the large apparatuses needed to simulate the flow in real pipelines. Rotating disk apparatus (RDA) is an instrument mainly comprising a rotating disk and an electrical motor to rotate the disk, which was implemented as an efficient and economical path to simulate what can be done in pipelines through generating a controlled degree of turbulence. This technique was also used in many other scientific applications due to its dynamic mode of operation. For example, a rotating disk electrode was used in electrodeposition processes and to characterize deposition film thickness and uniformity. The rotating disk reactor was employed to investigate the reaction rate between fluids and solid surfaces. The present work evaluates the RDA from different prospective and applications in order to introduce it as an efficient research tools for future dynamic investigations.

scholarly journals Calibration Method of Accelerometer Based on Rotation Principle Using Double Turntable Centrifuge

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 62
Author(s):  
Xianshan Dong ◽  
Xinlong Huang ◽  
Guizhen Du ◽  
Qinwen Huang ◽  
Yixiong Huang ◽  
...  
Keyword(s):  
Calculation Method ◽  
Calibration Method ◽  
Calibration Procedure ◽  
Scale Factor ◽  
Centripetal Acceleration ◽  
Mems Accelerometer ◽  
Key Technology ◽  
Acceleration Vector ◽  
Back Calculation ◽  
Input Acceleration

For linear accelerometers, calibration with a precision centrifuge is a key technology, and the input acceleration imposed on the accelerometer should be accurately obtained in the calibration. However, there are often errors in the installation of sample that make the calibration inaccurate. To solve installation errors and obtain the input acceleration in the calibration of the accelerometer, a calibration method based on the rotation principle using a double turntable centrifuge is proposed in this work. The key operation is that the sub-turntable is rotated to make the input axis of the accelerometer perpendicular to the direction of the centripetal acceleration vector. Models of installation errors of angle and radius were built. Based on these models, the static radius and input acceleration can be obtained accurately, and the calibration of the scale factor, nonlinearity and asymmetry can be implemented. Using this method, measurements of the MEMS accelerometer with a range of ±30 g were carried out. The results show that the discrepancy of performance obtained from different installation positions was smaller than 100 ppm after calibrating the input acceleration. Moreover, the results using this method were consistent with those using the back-calculation method. These results demonstrate that the effectiveness of our proposed method was confirmed. This method can measure the static radius directly eliminating the installation errors of angle and radius, and it simplifies the accelerometer calibration procedure.

Dynamics Modeling and Analysis of Riveted Mainframe Computer Structure

2017 ◽  
Author(s):  
Budy Notohardjono ◽  
Richard Ecker ◽  
Shawn Canfield
Keyword(s):  
Test Data ◽  
Dominant Mode ◽  
Mode Shapes ◽  
Dynamic Mode ◽  
Fe Model ◽  
Dynamics Modeling ◽  
Actual Structure ◽  
Beam Elements ◽  
Mainframe Computer ◽  
Riveted Joints

A typical mainframe computer rack is narrow, tall and long. In certain installations, during its functional operation, the server can be subjected to earthquake events. The rack is a steel structure joined together with steel rivets. One of the rack’s functions is to protect the critical components such as the processor, input-output and storage drawers from excessive motion by minimizing the amount of deflection. The riveted joints pose a challenge in accurately representing more than three thousand joints in a finite element (FE) model. In the FE model, bonding together sheet metal regions around the rivet joints will lead to a significantly stiffer model than the actual structure. On the other hand, an accurate representation of the riveted joints will lead to a better representation of the dynamic response of the server rack under vertical and horizontal loadings. This paper presents a method of analyzing rivet joints. The rivet joints are represented by beam elements with cylindrical cross-sections in the FE model. This is accomplished by identifying two parallel or overlapping plates and inserting discrete beam elements at the riveted joint. This method will be used to predict the dynamics modes of the structure. To validate the FE model, a prototype server rack was subjected to side to side vibration tests. A sine sweep vibration test identifies dominant mode shapes and the transmissibility of the input vibration. The results of the tests on the prototype rack serve as input for FE model refinement. The test data show that representing the riveted joints with beams does provide results that closely match the actual test data. A validated FE model will be used to evaluate dominant vibration modes for several configurations of rack weight as well as configurations to stiffen the structure in the side to side direction. The dynamic mode shapes visualize the effect of stiffening brackets on dominant frequencies of the rack. The optimal stiffening design will be the one that results in the minimum deflection under the standard testing profile.

scholarly journals Testing Volitional Qualities For Students Of High Schools Of Secondary School

2021 ◽  
Vol 03 (03) ◽  
pp. 405-413
Author(s):  
Dilmurod Yuldashevich Turdimurodov ◽  
Keyword(s):  
High School Students ◽  
Research Work ◽  
Breath Holding ◽  
Dynamic Mode ◽  
School Students ◽  
Level Of Evidence ◽  
Static Mode ◽  
Mode Of Operation ◽  
Education School ◽  
Different Levels

The article discusses the features of the manifestation of volitional qualities in high school students when performing tasks in the form of test exercises of a different nature. Based on the analysis of scientific and research work on the formation and development of volitional qualities, studies of the mid-education school, studies have been conducted by studies to identify the level of evidence in the performance of test exercises in the lessons of physical education. As test exercises, the researcher took and carried out: holding a dumbbell in front of him (for a while) with an outstretched arm (static mode of operation), work with a dumbbell for biceps with a strong arm for the number of times (dynamic mode of operation), breath holding test (for time). Tables of measurements of volitional component indices were compiled for students with different levels of motor activity (LMA) when performing tasks of a different nature. Indicators of the level of manifestation of volitional qualities of senior pupils in the experiment were assessed by the method of E.P. Shcherbakov.

scholarly journals An innovative technique of harvesting soil gas as a highly efficient source of 222Rn for calibration applications in a walk-in type chamber: part-1

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
N. Karunakara ◽  
Trilochana Shetty ◽  
B. K. Sahoo ◽  
K. Sudeep Kumara ◽  
B. K. Sapra ◽  
...  
Keyword(s):  
High Strength ◽  
Soil Gas ◽  
Dynamic Mode ◽  
Safety Issues ◽  
Highly Efficient ◽  
Mode Of Operation ◽  
Flow Through ◽  
Calibration Chamber ◽  
A New Technique ◽  
Calibration Laboratories

Abstract The paper describes a novel technique to harvest 222Rn laden air from soil gas of natural origin as a highly efficient source of 222Rn for calibration applications in a walk-in type 222Rn calibration chamber. The technique makes use of a soil probe of about 1 m to draw soil gas, through a dehumidifier and a delay volume, using an air pump to fill the calibration chamber. 222Rn concentration in the range of a few hundred Bq m−3 to a few tens of kBq m−3 was easily attained in the chamber of volume 22.7 m3 within a short pumping duration of 1 h. A new technique referred to as “semi-dynamic mode of operation” in which soil gas is injected into the calibration chamber at regular intervals to compensate for the loss of 222Rn due to decay and leak is discussed. Harvesting soil gas has many important advantages over the traditional methods of 222Rn generation for calibration experiments using finite sources such as solid flow-through, powdered emanation, and liquid sources. They are: (1) soil gas serves as an instantaneous natural source of 222Rn, very convenient to use unlike the high strength 226Ra sources used in the calibration laboratories, and has no radiation safety issues, (2) does not require licensing from the regulatory authority, and (3) it can be used continuously as a non-depleting reservoir of 222Rn, unlike other finite sources. The newly developed technique would eliminate the need for expensive radioactive sources and thereby offers immense application in a variety of day to day experiments—both in students and research laboratories.

A Linear Beam Finite Element Based on the Absolute Nodal Coordinate Formulation

2004 ◽  
Vol 127 (4) ◽  
pp. 621-630 ◽  
Author(s):  
Kimmo S. Kerkkänen ◽  
Jussi T. Sopanen ◽  
Aki M. Mikkola
Keyword(s):  
Absolute Nodal Coordinate Formulation ◽  
Longitudinal Direction ◽  
Beam Element ◽  
Computational Effort ◽  
Two Dimensional ◽  
Absolute Nodal Coordinate ◽  
Beam Elements ◽  
Shear Deformable Beam ◽  
The Absolute ◽  
Shear Deformable

In this paper, a new two-dimensional shear deformable beam element based on the absolute nodal coordinate formulation is proposed. The nonlinear elastic forces of the beam element are obtained using a continuum mechanics approach, without employing a local element coordinate system. In this study, linear polynomials are used to interpolate both the transverse and longitudinal components of the displacement. This is different from other absolute nodal-coordinate-based beam elements where cubic polynomials are used in the longitudinal direction. The use of linear interpolation polynomials leads to the phenomenon known as shear locking. This defect is avoided through the adoption of selective integration within the numerical integration method. The proposed element is verified using several numerical examples. The results of the proposed element are compared to analytical solutions and the results for an existing shear deformable beam element. It is shown that by using the proposed element, accurate linear and nonlinear static deformations, as well as realistic dynamic behavior including the capturing of the centrifugal stiffening effect, can be achieved with a smaller computational effort than by using existing shear deformable two-dimensional beam elements.

scholarly journals Estimation of Emissions During Monitoring of Pipelines in the Dynamic Mode of Operation

2016 ◽  
Vol 86 ◽  
pp. 04053 ◽  
Author(s):  
Maria Zemenkova ◽  
Yuri Zemenkov ◽  
Alexey Gladenko ◽  
Sergey Podorozhnikov
Keyword(s):  
Dynamic Mode ◽  
Mode Of Operation
Sign in / Sign up

Export Citation Format

Share Document