A Study on Micro Strain Electrorheological Damper Model

2007 ◽  
Author(s):  
Yaying Chen ◽  
Yu Zhu ◽  
Guanghong Duan ◽  
Jia Cheng
Keyword(s):  
Experimental Data ◽  
Electric Fields ◽  
Strain State ◽  
Constant Term ◽  
Optimal Parameters ◽  
Plastic Model ◽  
Ultra Precision ◽  
Stage System ◽  
Width Change ◽  
Gas Bearing

This paper presents experimental and theoretical model analysis of an electrorheological damper operating in the micro strain state. An ER shear damper is developed and installed on an established ultra-precision gas bearing stage system. The damper characteristics of force vs. velocity responses under various electric fields and excitation frequencies are obtained. To describe the practical damper characteristics, a modified Eyring-plastic model is proposed, which differ from the original Eyring-plastic model by adding a constant term. The constant term can compensate the curve error induced by the width change of the pre-yield hysteresis loop. Based on optimal parameters identification, the modified Eyring-plastic model fits the experimental data more closely. So it is more accurate to express the electrorheological shear damper characteristics operating in the region of micro strain.

Development of designing and implementation method of magnetic execution unit of downhole valve for the bottomhole assembly

2020 ◽  
pp. 38-44
Author(s):  
I.Y. Shirali ◽  
◽  
V.Yu. Tsivilitsin ◽  
İ.B. Bondar ◽  
R.A. Hasanov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Theoretical Calculations ◽  
Calculation Methods ◽  
Well Drilling ◽  
Power Characteristics ◽  
Drilling Tools ◽  
Execution Unit ◽  
Implementation Method ◽  
Oil Gas ◽  
Gas Bearing

The structure of two types of magnetic valve is offered and the calculation methods of their pull-in force developed as well. The formulas of calculation of pull-in force in the main area of valves’ power characteristics are obtained. Experimental data are in alignment with theoretical calculations. Power characteristics of offered structures of magnetic valves may be changed in terms of the offered structural execution of magnetic valves. Experimental test of obtained formulas has been carried out. The ways of changing the power characteristics of magnetic valves in accordance with the requirements of certain applications are presented. The structures of magnetic reversing valves for drilling tools used in well drilling in various oil-gas bearing areas of SOCAR have been developed.

The Mechanical Modeling of Oxygen-Containing Precipitates in Silicon Wafers on Different Stages of the Getter Formation Process

2011 ◽  
Vol 178-179 ◽  
pp. 483-488
Author(s):  
Pavel S. Shushpannikov ◽  
Robert V. Goldstein ◽  
Konstantin Ustinov
Keyword(s):  
Experimental Data ◽  
Silicon Wafer ◽  
Formation Process ◽  
Strain State ◽  
Spherical Shape ◽  
Point Of View ◽  
Dislocation Loops ◽  
Mechanical Modeling ◽  
Silicon Matrix ◽  
Spheroidal Inclusion

The behavior of the oxygen-containing precipitate in silicon wafer on different stages of the getter formation process is considered from the mechanical point of view. The precipitate is modeled as a spheroidal inclusion undergoing inelastic eigenstrains in an anisotropic silicon matrix. The stress-strain state in the precipitate and matrix is calculated within the framework of the model. An energetic criterion of breaking the spherical shape by the coherent precipitates is obtained and analyzed. Criteria of the formation and onset of motion of the dislocation loops in the vicinity of the precipitate are also proposed. The obtained results are compared with the available experimental data.

scholarly journals Numerical and experimental investigations of steel-concrete beams with thin-walled section

Vestnik MGSU ◽  
2019 ◽  
pp. 22-32
Author(s):  
Farit S. Zamaliev
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Strain State ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Numerical Studies ◽  
Field Samples ◽  
Thin Walled

Introduction. Conducted is to the evaluation of the stress-strain state of the steel-concrete beams with thin-walled section. In recent times, steel-reinforced concrete structures have become widely used in civilian buildings (beams, slabs, columns). Thin-walled section have not found wide application in steel concrete structures, unlike steel structures. Presents the results of numerical studies of beams consisting of concrete, anchors and steel beams. Two investigating of the location of anchors are given. Numerical investigations are presented of steel-concrete beams with thin-walled section based on numerical studies. Testing procedure and test result are given. Results of calculations, comparison of numerical and experimental studies are presented. Materials and methods. For full-scale experiments, steel I-beams with filling of side cavities with concrete were adopted, screws are used as anchor ties, with varied both the lengths and their location (vertically and obliquely). As steel curved C-shaped steel profiles were used steel profiles from the range of the company “Steel Faces”. ANSYS software package was used for computer modeling. A total of 16 steel concrete beams were considered, for which the results of strength and stiffness evaluation were obtained in ANSYS. Results. The data of the stress-strain state of beams on the basis of computer simulation are obtained. The results are used for the production of field samples. Data of computer simulation are compared with the indicators of field experiments. Conclusions. The stress-strain state of steel-concrete structures was studied on the basis of numerical and experimental data. The proposed calculation method gives good convergence with the experimental data. Anchor connections made from self-tapping screws can be used in studies for modeling in steel-concrete beams structures and other anchor devices, ensuring the joint operation of concrete and steel profiles in structures.

A Calculation Method to Investigate the Effects of Geometric Parameters and Operational Conditions on the Static Characteristics of Aerostatic Spherical Bearings

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Hailong Cui ◽  
Huan Xia ◽  
Dajiang Lei ◽  
Xinjiang Zhang ◽  
Zhengyi Jiang
Keyword(s):  
Experimental Data ◽  
Calculation Method ◽  
Reynolds Equation ◽  
Geometric Parameters ◽  
Static Characteristics ◽  
Optimal Parameters ◽  
Film Pressure ◽  
Operational Conditions ◽  
Pressure Distributions ◽  
Calculation Results

In this paper, a calculation method based on matlab partial differential equations (PDE) tool is proposed to investigate the static characteristics of aerostatic spherical bearings. The Reynolds equation of aerostatic spherical bearings is transformed into a standard elliptic equation. The effects of geometric parameters and operational conditions on the film pressure, bearing film force, and stiffness are studied. The axial and radial eccentricities result in different film pressure distributions; the bearing film force and stiffness are significantly influenced by geometric parameters and operational conditions. The relative optimal parameters are confirmed based on the calculation results. A comparison between the numerical and experimental results is also presented. The highest relative error between the numerical results and the experimental data is 11.3%; the calculation results show good agreements with the experimental data, thus verifying the accuracy of the calculation method used in this paper.

Electrostatic Generation in Dielectric Fluids: The Viscoelectric Effect

2005 ◽  
Author(s):  
Robert T. Balmer
Keyword(s):  
Experimental Data ◽  
Electric Fields ◽  
Theoretical Basis ◽  
Fluid Motion ◽  
Irreversible Thermodynamics ◽  
Reverse Effect ◽  
Dielectric Fluids ◽  
Electrostatic Generator ◽  
New Type ◽  
Mobile Charges

Simultaneous energy transfer modes have been known to interact to produce unusual “coupled” effects. This coupling now has its theoretical basis in the concept of entropy production (or dissipation or irreversibility) central to nonequilibrium irreversible thermodynamics. Over the years, many examples of coupled phenomena have been identified and studied (thermoelectricity, electrokinetics, piezoelectricity, and so forth). Electrohydrodynamics (the effect of fluid motion on electric fields and the reverse effect of electric fields on fluid motion) can be explained as a thermodynamically coupled phenomenon characterized by the viscous and electrical properties of a fluid that contain mobile charges at the molecular (e.g., ions) or macroscopic (e.g., dust) levels. This is called the “viscoelectric” effect. In the first part of this paper we apply the concepts of irreversible thermodynamics to electrohydrodynamic systems to develop the relevant relationships. The second describes experiments carried out with a new type of Couette electrostatic generator. The resulting experimental data is then discussed in light of the coupled phenomenon relations previously developed.

ELECTROMAGNETIC FIELDS IN AN N‐LAYER ANISOTROPIC HALF‐SPACE

Geophysics ◽  
1967 ◽  
Vol 32 (4) ◽  
pp. 668-677 ◽  
Author(s):  
Douglas P. O’Brien ◽  
H. F. Morrison
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Plane Wave ◽  
Half Space ◽  
Electric Fields ◽  
Field Measurements ◽  
Large Scatter ◽  
Tensor Impedance ◽  
The Magnetic Field ◽  
Made In

From Maxwell’s equations and Ohm’s law for a horizontally anisotropic medium, it may be shown that two independent plane wave modes propagate perpendicular to the plane of the anisotropy. Boundary conditions at the interfaces in an n‐layered model permit the calculation, through successive matrix multiplications, of the fields at the surface in terms of the fields propagated into the basal infinite half space. Specifying the magnetic field at the surface allows the calculation of the resultant electric fields, and the calculation of the entries of a tensor impedance relationship. These calculations have been programmed for the digital computer and an interpretation of impedances obtained from field measurements may thus be made in terms of the anisotropic layering. In addition, apparent resistivities in orthogonal directions have been calculated for specific models and compared to experimental data. It is apparent that the large scatter of observed resistivities can be caused by small changes in the polarization of the magnetic field.

Interplay between Fracture and Domain Switching of Ferroelectrics

2006 ◽  
Vol 306-308 ◽  
pp. 501-510
Author(s):  
Y.Q. Cui ◽  
Wei Yang
Keyword(s):  
Experimental Data ◽  
Crack Initiation ◽  
Electric Fields ◽  
Large Scale ◽  
Inner Core ◽  
Domain Switching ◽  
Global Scale ◽  
Theoretical Predictions ◽  
T Stress ◽  
Cylindrical Inclusions

Applications of above-coercive electric fields lead to domain switching of a large or global scale. Large scale switching model is proposed to deal with load-induced domains witching in experiment. Both a discussion of crack initiation via the stress intensity factor and a discussion of crack path stability via T-stress are presented. The theoretical predictions and the experimental data roughly coincide for crack initiation, propagation and stability phenomena. Attention is also extended to consider the effect of non-uniform ferro-elastic domain switching in the vicinity of a crack. The domain switching zone is divided into a saturated inner core and an active surrounding annulus. Toughening for ferroelectrics with different poling states is estimated via Reuss type approximation. Solutions obtained according to spherical and cylindrical inclusions cover the range of experimental data.

scholarly journals Toward the cottonization of hemp fibers by steam explosion – Part 1: defibration and morphological characterization

2017 ◽  
Vol 88 (9) ◽  
pp. 1047-1055 ◽  
Author(s):  
Thibaud Sauvageon ◽  
Jean-Michel Lavoie ◽  
César Segovia ◽  
Nicolas Brosse
Keyword(s):  
Experimental Data ◽  
Image Processing ◽  
Response Surface Methodology ◽  
Steam Explosion ◽  
Morphological Characterization ◽  
Optimal Parameters ◽  
Hemp Fibers ◽  
Alkali Hydrolysis ◽  
Central Composite ◽  
Good Agreement

Fine hemp fibers (cottonized hemp) were processed using steam explosion. The quantification of the defibration rate was performed by image processing. Based on this method, the hemp defibration was optimized using a response surface methodology based on three-variable central composite design for the production of elementary fibers with low variability. Optimal parameters for the steam processes were as follows: time = 4.1 min; temperature = 191℃. Biomass was impregnated with a solution of NaOH (8%) before treatment, leading to a defibration rate of 91.2%, which is producing ≈50% fibers with length <3 mm, in good agreement with the experimental data. Damaged fibers originating from the conjugated effect of steam explosion and alkali hydrolysis were also observed.

Experimental and theoretical investigations of optical properties of GaN/AlGaN MQW nanostructures. Impact of built-in polarization fields

2009 ◽  
Vol 17 (4) ◽  
Author(s):  
M. Esmaeili ◽  
M. Gholami ◽  
H. Haratizadeh ◽  
B. Monemar ◽  
P. Holtz ◽  
...  
Keyword(s):  
Experimental Data ◽  
Quantum Wells ◽  
Electric Fields ◽  
Heavy Hole ◽  
Multiple Quantum ◽  
Interface Charges ◽  
Peak Energy ◽  
Theoretical Investigations ◽  
Electron Ground State ◽  
Good Agreement

AbstractWe report the results from detailed optical spectroscopy from MOCVD grown GaN/AlGaN multiple quantum wells (MQWs), as opposed to most previous studies where MBE was employed by means of photoluminescence (PL) technique. In this paper we will present theoretical and experimental results demonstrating how polarization induced electric fields and bound interface charges in GaN/AlGaN MQWs affect the emission peak energy, PL line shape, as well as the emission line width. Theoretically estimated fields in this work are consistent with experimental data. Transition energy of the heavy hole and electron ground state Ee-hh in GaN/AlGaN MQWs were calculated and it is found that it stays in good agreement with the experimental data.

Calibration of a Shear Specimen

2016 ◽  
Vol 254 ◽  
pp. 138-143
Author(s):  
Daniel Iosif Maxim ◽  
Liviu Marşavina ◽  
Mircea Cristian Dudescu
Keyword(s):  
Experimental Data ◽  
Sheet Metal ◽  
Shear Test ◽  
Shear Failure ◽  
Pure Shear ◽  
Stress Fields ◽  
Virtual Model ◽  
Shear Tests ◽  
Plastic Model ◽  
Steel Material

Different geometries of shear test specimens were experimentally and numerically investigated. They are used for calibration of a virtual model, to be used for sheet metal blanking. Different specimen configurations were simulated in order to determine the strain and stress fields and the potential of producing pure shear failure. Tensile and shear tests were performed using DC01 steel material. The experimental data are used later to calibrate a material with Johnson-Cook elastic-plastic model.

Sign in / Sign up

Export Citation Format

Share Document