The Effect of Stepped Field Shaper on Magnetic Pressure and Radial Displacement in Electromagnetic Inside Bead Forming: Experimental and Simulation Analyses Using maxwell and abaqus Software

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Rasoul Chaharmiri ◽  
Alireza Fallahi Arezoodar
Keyword(s):  
Radial Displacement ◽  
Experimental Tests ◽  
Magnetic Pressure ◽  
Geometric Parameters ◽  
Electrically Conductive ◽  
Mechanical Parts ◽  
Forming Technology ◽  
Pressure Concentration ◽  
High Strain Rate Forming ◽  
Abaqus Software

Electromagnetic forming (EMF) is a high strain rate forming technology which can effectively deform and shape high electrically conductive materials at room temperature. A field shaper is frequently used for concentrating the magnetic pressure in the desired forming area. The geometric parameters of a field shaper, as an intermediate device, affect the magnetic pressure and radial displacement in electromagnetic inside bead forming. EMF consists of electromagnetic and mechanical parts simulated using maxwell and abaqus software, respectively. The effects of geometric parameters of the stepped field shaper on magnetic pressure and radial displacement were investigated, and the best parameters were determined. Experimental tests were performed at various discharge voltages and the results were compared with simulation. The results indicated that using the stepped field shaper, the magnetic pressure concentration ratio increased from about 23–85% in comparison with using a direct coil. The maximum magnetic pressure increased by approximately 21% due to the effective concentration of magnetic pressure. Consequently, regardless of the electromagnetic energy losses because of using a field shaper, the radial displacement increased by 8% in simulation and 6% in experiment. The result of this study would be also helpful in designing field shapers in similar applications which is highly crucial and strongly recommended.

scholarly journals Passive Measurement of Three Optical Beacon Coordinates Using a Simultaneous Method

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5235
Author(s):  
Jiri Nemecek ◽  
Martin Polasek
Keyword(s):  
Mathematical Model ◽  
Relative Position ◽  
Experimental Tests ◽  
Image Sensor ◽  
Geometric Parameters ◽  
Light Sources ◽  
Feature Points ◽  
Passive Measurement ◽  
The Mathematical Model ◽  
Physical Principles

Among other things, passive methods based on the processing of images of feature points or beacons captured by an image sensor are used to measure the relative position of objects. At least two cameras usually have to be used to obtain the required information, or the cameras are combined with other sensors working on different physical principles. This paper describes the principle of passively measuring three position coordinates of an optical beacon using a simultaneous method and presents the results of corresponding experimental tests. The beacon is represented by an artificial geometric structure, consisting of several semiconductor light sources. The sources are suitably arranged to allow, all from one camera, passive measurement of the distance, two position angles, the azimuth, and the beacon elevation. The mathematical model of this method consists of working equations containing measured coordinates, geometric parameters of the beacon, and geometric parameters of the beacon image captured by the camera. All the results of these experimental tests are presented.

scholarly journals Decayless Kink Oscillations Excited by Random Driving: Motion in Transitional Layer

Solar Physics ◽  
2021 ◽  
Vol 296 (8) ◽  
Author(s):  
M. S. Ruderman ◽  
N. S. Petrukhin ◽  
E. Pelinovsky
Keyword(s):  
Coronal Loop ◽  
Radial Displacement ◽  
Oscillation Amplitude ◽  
Radial Distance ◽  
Magnetic Pressure ◽  
Pressure Perturbation ◽  
Transitional Layer ◽  
Thin Boundary Layer ◽  
Plasma Displacement ◽  
Thin Tube

AbstractIn this article we study the plasma motion in the transitional layer of a coronal loop randomly driven at one of its footpoints in the thin-tube and thin-boundary-layer (TTTB) approximation. We introduce the average of the square of a random function with respect to time. This average can be considered as the square of the oscillation amplitude of this quantity. Then we calculate the oscillation amplitudes of the radial and azimuthal plasma displacement as well as the perturbation of the magnetic pressure. We find that the amplitudes of the plasma radial displacement and the magnetic-pressure perturbation do not change across the transitional layer. The amplitude of the plasma radial displacement is of the same order as the driver amplitude. The amplitude of the magnetic-pressure perturbation is of the order of the driver amplitude times the ratio of the loop radius to the loop length squared. The amplitude of the plasma azimuthal displacement is of the order of the driver amplitude times $\text{Re}^{1/6}$ Re 1 / 6 , where Re is the Reynolds number. It has a peak at the position in the transitional layer where the local Alfvén frequency coincides with the fundamental frequency of the loop kink oscillation. The ratio of the amplitude near this position and far from it is of the order of $\ell$ ℓ , where $\ell$ ℓ is the ratio of thickness of the transitional layer to the loop radius. We calculate the dependence of the plasma azimuthal displacement on the radial distance in the transitional layer in a particular case where the density profile in this layer is linear.

Experimental Investigation and Characterization of the Rotating Stall in a High Pressure Centrifugal Compressor: Part II — Influence of Diffuser Geometry on Stage Performance

2002 ◽  
Author(s):  
G. Ferrara ◽  
L. Ferrari ◽  
C. P. Mengoni ◽  
M. De Lucia ◽  
L. Baldassarre
Keyword(s):  
Experimental Tests ◽  
Rotating Stall ◽  
Geometric Parameters ◽  
Flow Coefficient ◽  
Low Flow ◽  
Main Task ◽  
Stage Performance ◽  
The Impact ◽  
Prediction Criteria

Extensive research on centrifugal compressors has been planned. The main task of the research is to improve present prediction criteria coming from the literature with particular attention to low flow coefficient impellers (low width to radius ratios) where they are no more valid. Very little data has been published for this kind of stages, especially for the last stage configuration (with discharge volute). Many experimental tests have been planned to investigate different configurations. A simulated stage with a backward channel upstream, a 2D impeller with a vaneless diffuser and a constant cross section volute downstream constitute the basic configuration. Several diffuser types with different widths, pinch shapes and diffusion ratios were tested. The effect of geometric parameters on stage stability has been discussed inside part I of the present work; the purpose of this part of the work is to illustrate the effect of the same geometric parameters on stage performance and to quantify the impact of stability improvements on stage losses.

Evaluation of drawing force by a new dimensionless method in deep drawing process

2020 ◽  
Vol 234 (13) ◽  
pp. 1604-1614
Author(s):  
Saeed Hajiahmadi ◽  
Majid Elyasi ◽  
Mohsen Shakeri
Keyword(s):  
Coefficient Of Friction ◽  
Deep Drawing ◽  
Experimental Tests ◽  
Geometric Parameters ◽  
Relational Model ◽  
Geometrical Parameters ◽  
Drawing Force ◽  
Dimensionless Parameters ◽  
Dimensionless Analysis ◽  
The Coefficient Of Friction

In this research, geometric parameters were given in dimensionless form by the Π- Buckingham dimensional analysis method in the dimensionless group for deep drawing of a round cup. To find the best group of dimensionless parameters and the fittest dimensionless relational model, three scales of the cup are evaluated numerically by a commercial finite element software and stepwise regression modeling. After analyzing all effective geometric parameters, a fittest relational model among dimensionless parameters is found. In addition, the results of the new dimensionless model were compared with the simulation process and experimental tests. From the results, it is inferred that the geometric qualities of a large scale can be predicted with a small scale by the proposed dimensionless model. Comparing the results of the dimensionless model with experimental tests shows that the proposed dimensionless model has fine precision in the determination of geometrical parameters and drawing force estimation. Moreover, to evaluate the accuracy of the proposed dimensionless model, the predicted value of the model has been compared by the experimental results. It is shown that the dimensionless ratios of geometrical parameters can significantly affect the estimation of the drawing force by the proposed dimensionless model, but based on similarity law, because of the constant value of these dimensionless parameters in different scales, they could not be used for dimensionless analysis separately. It is also inferred that because of the effect of contact area on the coefficient of friction, which is changed by scale changing, the only dimensionless parameter that can significantly change the drawing force is the coefficient of friction. Finally, it is shown that the dimensionless geometrical parameter and the coefficient friction should be combined for dimensionless analysis.

scholarly journals Investigation of a new methodology for the prediction of drawing force in deep drawing process with respect to dimensionless analysis

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Saeed Hajiahmadi ◽  
Majid Elyasi ◽  
Mohsen Shakeri
Keyword(s):  
Deep Drawing ◽  
Large Scale ◽  
Model Comparison ◽  
Experimental Tests ◽  
Geometric Parameters ◽  
Relational Model ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Drawing Force ◽  
Force Estimation

AbstractIn this research, geometric parameters were given in dimensionless form by the Buckingham pi dimensional analysis method, and a series of dimensionless groups were found for deep drawing of the round cup. To find the best group of dimensionless geometric parameters, three scales are evaluated by commercial FE software. After analyzing all effective geometric parameters, a fittest relational model of dimensionless parameters is found. St12 sheet metals were used for experimental validation, which were formed at room temperature. In addition, results and response parameters were compared in the simulation process, experimental tests, and proposed dimensionless models. By looking at the results, it very well may be inferred that geometric qualities of a large scale can be predicted with a small scale by utilizing the proposed dimensionless model. Comparison of the outcomes for dimensionless models and experimental tests shows that the proposed dimensionless models have fine precision in determining geometrical parameters and drawing force estimation. Moreover, generalizing proposed dimensionless model was applied to ensure the estimating precision of geometric values in larger scales by smaller scales.

scholarly journals Experimental tests of vehicle body accelerations at selected road and rail crossings

2019 ◽  
Vol 254 ◽  
pp. 04002 ◽  
Author(s):  
Konrad J. Waluś ◽  
Jakub Polasik ◽  
Janusz Mielniczuk ◽  
Łukasz Warguła
Keyword(s):  
Cross Section ◽  
Experimental Tests ◽  
The Body ◽  
Geometric Parameters ◽  
Vehicle Body ◽  
Delivery Vehicle ◽  
Dynamic Reaction ◽  
Level Crossing ◽  
Level Crossings ◽  
Section Structure

Vehicles moving across the railway are exposed to the dynamic reaction of unevenness of surface on those level crossing. This significantly influences on the increase of the acceleration as well as forces values transferred to the body of the car. These values depend to extent on the geometric parameters of level crossing as well as on the characteristics of the car tires and suspension. The paper presents the results of experimental tests of a small delivery vehicle crossing selected level crossings with a diversified geometric cross-section structure.

Numerical analysis of electrically conductive fillers of composites for aircraft lightning strike protection

2020 ◽  
Vol 92 (10) ◽  
pp. 1441-1450
Author(s):  
Igor Lesiuk ◽  
Andrzej Katunin
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Numerical Analysis ◽  
Numerical Models ◽  
Experimental Tests ◽  
Lightning Strike ◽  
Electrically Conductive ◽  
Content Type ◽  
Conductive Composites ◽  
Conductive Fillers

Purpose This paper aims to present a numerical analysis and comparison of two types of conductive fillers of polymeric composites subjected to lightning strikes. Design/methodology/approach Two types of conductive fillers were considered in the developed numerical models of electrically conductive composites: carbon nanotubes and polyaniline. For these fillers, the representative volume elements were developed to consider distribution of the particles that ensures percolation and homogenization of the materials within the Eshelby-based semi-analytical mean-field homogenization approach. The performed numerical analyses allowed determination of effective volume fractions of conducting particles, resistivity and conductivity tensors, and finally the current density for the simulated materials subjected to lightning strike. Findings The obtained results allowed for comparison of electrical conductivity of two simulated materials. It was observed that besides fair results obtained in the previous studies for intrinsically conducting polymers as fillers of composites dedicated for lightning strike protection, the composites filled with carbon nanotubes reveal much better conductivity. Practical implications The presented simulation results can be considered as initial information for further experimental tests on electrical conductivity of such materials. Originality/value The originality of the paper lies in the proposed design and simulation procedures of conductive composites as well as the comparison of selected composites dedicated for lightning strike protection as the most intensively developed materials for this purpose.

The Deformation Process of Thin-Walled Box Beams Joined by Rivets under Three-Point Bending

2016 ◽  
Vol 254 ◽  
pp. 283-289
Author(s):  
Tomasz Sadowski ◽  
Marek Nowicki ◽  
Daniel Pietras ◽  
Przemysław Golewski
Keyword(s):  
Deformation Process ◽  
Mechanical Response ◽  
Experimental Tests ◽  
Equivalent Stiffness ◽  
Element Analysis ◽  
Three Point Bending ◽  
Flat Sheet ◽  
Box Beams ◽  
Thin Walled ◽  
Abaqus Software

This paper is focused on description of the mechanical response of the aluminum box-beams subjected to 3 point bending (3-PB). The main aim of this paper is to determine the effect of spacing between rivets on the equivalent stiffness and strength of the analised profile. The considered beams are composed of two sections: one of them is an aluminum omega profile and another is a composite flat sheet. Experimental tests were carried out for various spacing between rivets. Moreover, the corresponding numerical analyses by Finite Element Analysis (FEA) with application of the Abaqus software were done for estimate of the mechanical response of the box beams. The results show relationship between spacing of the rivets and values of carrying forces.

scholarly journals Theoretical modeling of the vertical stiffness of a rolling lobe air spring

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094089
Author(s):  
Liufeng Xu
Keyword(s):  
Analytical Model ◽  
Ride Comfort ◽  
Experimental Tests ◽  
Geometric Parameters ◽  
Air Spring ◽  
Vertical Stiffness ◽  
Approximate Analytic Method ◽  
Proposed Model ◽  
Stiffness Characteristics ◽  
The Relationship

In order to study the characteristics of a rolling lobe air spring, a vertical stiffness analytical model is constructed based on thermodynamics and hydrodynamics. The merit of this vertical stiffness analytical model is that an analytical solution of geometric parameters is obtained by an approximate analytic method. Meanwhile, experimental tests are carried out to verify the accuracy of the vertical stiffness analytical model. The vertical stiffness analytical model can be used to qualitatively analyze the influence of geometric parameters on the vertical stiffness characteristics of a rolling lobe air spring. Therefore, the relationship between geometric parameters and the vertical stiffness characteristics is analyzed based on the proposed model. The conclusions show that the vertical stiffness analytical model can well predict the mechanical characteristics of a rolling lobe air spring and provide guidance for parameter design and vehicle ride comfort improvement.

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