Numerical Simulation and Analysis on Magnetizing Exciter for Magnetic Flux Leakage

2011 ◽  
Vol 474-476 ◽  
pp. 1187-1190
Author(s):  
Qiang Song
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Magnetic Flux Leakage ◽  
Magnetic Flux Density ◽  
Outer Diameter ◽  
Element Analysis ◽  
Flux Leakage

Magnetic flux leakage (MFL) is a non-destructive testing method used to inspect the pipe and magnetization of the pipe wall to saturation is essential for anomalies to be reliably and accurately detected and characterized. Axial components of magnetic flux density obtained during the MFL inspection have been simulated using three-dimensional finite element analysis and the effects of magnetizing exciter parameters on magnetic flux density are investigated. The pipe modeled in this paper has an outer diameter of 127mm (5 in.) with a wall thickness of 9 mm (0.354 in.). According to numerical simulations, an increase in the magnetic flux density of pipe wall is observed with an increase in the permanent magnet length and height. It clearly illustrates that Nd-Fe-B permanent magnet assembly with 70 mm length and 40 mm height may magnetize pipe wall to near saturation.

Finite Element Analysis on Magnetic Flux Leakage of Interior Permanent Magnet Generator for Vehicle

2011 ◽  
Vol 66-68 ◽  
pp. 483-488 ◽  
Author(s):  
Xue Yi Zhang ◽  
Hong Bin Yin ◽  
Li Wei Shi
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Structural Design ◽  
Magnetic Flux Leakage ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Interior Permanent Magnet ◽  
Leakage Coefficient ◽  
Flux Leakage

In order to solve the problem that no-load magnetic flux leakage coefficient is not accurate when it is calculated by the method of magnetic circuit, a model of interior permanent magnet(IPM) generator with 36 slots for vehicle was built through the finite element method of the ANSYS, and then a means of calculating the IPM generator’s magnetic flux was put forward after analyzing the magnetic flux leakage conditions of different rotor structures under the circumstance of not changing stator structure. The ralationships among the pairs of poles, the magnet width, the thickness of non-magnetic sleeve, the length of air-gap and the magnetic flux leakage coefficient were obtained, and they provided forceful guidance for the structural design of IPM generator.

Understanding Magnetic Flux Leakage Signals From Dents

2006 ◽  
Author(s):  
Lynann Clapham ◽  
Vijay Babbar ◽  
Alex Rubinshteyn
Keyword(s):  
Magnetic Flux ◽  
Pipe Wall ◽  
Experimental Studies ◽  
Mechanical Damage ◽  
Magnetic Behaviour ◽  
Magnetic Flux Leakage ◽  
Element Analysis ◽  
Aspect Ratios ◽  
Stress Relieving ◽  
Flux Leakage

The Magnetic Flux Leakage (MFL) technique is sensitive both to pipe wall geometry and pipe wall stresses, therefore MFL inspection tools have the potential to locate and characterize mechanical damage in pipelines. However, the combined influence of stress and geometry make MFL signal interpretation difficult for a number of reasons: 1) the MFL signal from mechanical damage is a superposition of geometrical and stress effects, 2) the stress distribution around a mechanically damaged region is very complex, consisting of plastic deformation and residual (elastic) stresses, 3) the effect of stress on magnetic behaviour is not well understood. Accurate magnetic models that can incorporate both stress and geometry effects are essential in order to understand MFL signals from dents. This paper reports on work where FEA magnetic modeling is combined with experimental studies to better understand dents from MFL signals. In experimental studies, mechanical damage was simulated using a tool and die press to produce dents of varying aspect ratios (1:1, 2:1, 4:1), orientations (axial, circumferential) and depths (3–8 mm) in plate samples. MFL measurements were made before and after selective stress-relieving heat treatments. These annealing treatments enabled the stress and geometry components of the MFL signal to be separated. Geometry and stress ‘peaks’ tend in most cases to overlap — however stress features are most prominent in the dent rim region and geometry peaks over central region. In general the geometry signal scales directly with depth. The stress scales less significantly with depth. As a result deep dents will display a ‘geometry’ signature while in shallow dents the stress signature will dominate. In the finite element analysis work, stress was incorporated by modifying the magnetic permeability in the residual stress regions of the modeled dent. Both stress and geometry contributions to the MFL signal were examined separately. Despite using a number of simplifying assumptions, the modeled results matched the experimental results very closely, and were used to aid in interpretation of the MFL signals.

3D Finite Element Analysis for Magnetic Flux Leakage Testing

2011 ◽  
Vol 201-203 ◽  
pp. 1623-1626
Author(s):  
Qiang Song
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Flux ◽  
Three Dimensional ◽  
Magnetic Flux Leakage ◽  
Destructive Testing ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Flux Leakage

Magnetic flux leakage (MFL) is a non-destructive testing method used to inspect ferrous materials. However, apparatus parameters could affect the MFL inspection tool’s ability to characterize anomalies. In this paper, MFL signals obtained during the inspection of pipes have been simulated using three-dimensional finite element analysis and the effects of magnet assembly on MFL signals are investigated. According to numerical simulations, an increase in the leakage flux amplitude is observed with an increase in the permanent magnet size and the inflexion point may indicate the presence of magnetizing pipe wall to near saturation. It clearly illustrates degradation in the MFL with increasing backing iron length. The relationship between MFL apparatus parameters and MFL signals could be utilized in the MFL technique to characterize the defect.

scholarly journals Theoretical Analysis of the Rectangular Defect Orientation using Magnetic Flux Leakage

2018 ◽  
Vol 18 (1) ◽  
pp. 28-34
Author(s):  
J. Sam Alaric ◽  
V. Suresh ◽  
A. Abudhahir ◽  
M. Carmel Sobia ◽  
M. Baarkavi
Keyword(s):  
Magnetic Flux ◽  
Analytical Model ◽  
Three Dimensional ◽  
Tangential Component ◽  
Magnetic Flux Leakage ◽  
Axial Component ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Flux Leakage

Abstract This paper presents an approach to estimate the orientation of the rectangular defect in the ferromagnetic specimen using the magnetic flux leakage technique. Three components of the magnetic flux leakage profile, such as radial, axial, and tangential component are considered to estimate the orientation of the rectangular defect. The orientation of the rectangular defect is estimated by the proposed analytical model using MATLAB software. The results calculated by the analytical model are validated by the three-dimensional finite element analysis using COMSOL Multiphysics software. Tangential component provides better performance to estimate the orientation of the rectangular defect compared with radial and axial component of the magnetic flux leakage profile.

Modelling Magnetic Flux Leakage Signals From Dents

2008 ◽  
Author(s):  
Lynann Clapham ◽  
Vijay Babbar ◽  
Kris Marble ◽  
Alex Rubinshteyn ◽  
Mures Zarea
Keyword(s):  
Magnetic Flux ◽  
Pipe Wall ◽  
Mechanical Damage ◽  
Magnetic Behaviour ◽  
Magnetic Flux Leakage ◽  
Element Analysis ◽  
The Past ◽  
Fea Modeling ◽  
Flux Leakage ◽  
Wall Geometry

The Magnetic Flux Leakage (MFL) technique is sensitive both to pipe wall geometry and pipe wall strain, therefore MFL inspection tools have the potential to locate and characterize mechanical damage in pipelines. However, the combined influence of strain and geometry makes MFL signals from dents and gouges difficult to interpret for a number of reasons: 1) the MFL signal from mechanical damage is a superposition of geometrical and strain effects, 2) the strain distribution around a mechanically damaged region can be very complex, often consisting of plastic deformation and residual (elastic) strain, 3) the effect of strain on magnetic behaviour is not well understood. Accurate magnetic models that can incorporate both strain and geometry effects are essential in order to understand MFL signals from mechanical damage. This paper reviews work conducted over the past few years involving magnetic finite element analysis (FEA) modeling of MFL dent signals and comparison with experimental results obtained both from laboratory-dented samples and dented pipe sections.

scholarly journals Analysis Of Eddy Current Loss Of IPMSM According To The Material Of Permanent Magnet

2021 ◽  
Vol 12 (6) ◽  
pp. 508-513
Author(s):  
Byeong-Chul Lee Et.al
Keyword(s):  
Finite Element Analysis ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Eddy Current Losses ◽  
Current Loss

 In order to reach the performance of the permanent magnet embedded rotor, the choice of magnet is very important. It must be thermally stabilized, and at this point, discussion of eddy current losses is necessary.To proceed with this study, a permanent magnet embedded synchronous motor used in the compressor currently being designed was selected. To derive the eddy current losses in the neodymium-magnets, current density was calculated through the equation. The eddy current loss was mathematically derived using the magnetic conductivity and residual magnetic flux density. Finally, comparative verification was performed through finite element analysis simulation. In this paper, eddy current losses in a N series magnet are mathematically analyzed and we perform comparative verification through simulation using finite element analysis. The Br value indicating the residual magnetic flux density is the lowest in N30 series and the largestin the N48 series. In the case of using the N30 series, the amount of magnetic flux that can be generated is low, so in order to increase the same output, the electric field must be increased by drawing more current from the stator winding. That is, the torque can be further increased. However, since the magnetic flux density experienced by the permanent magnet also increases, eddy current loss that may occur in the  magnet eventually increases. There are also a method of using a split magnet to reduce eddy current losses. Inthe case of a permanent magnet holding a large residual magnetic flux density, the magnets loss is reduced, but there is a disadvantage that the price may be expensive. The losses in the permanent magnet are dissipated as heat. If the eddy current loss increases, the magnet demagnetizes, which in turn leads to a decrease in performance. In the selection of magnets, analysis of losses is essential.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

scholarly journals DESIGN OF A SINGLE-PHASE RADIAL FLUX PERMANENT MAGNET GENERATOR WITH VARIATION OF THE STATOR DIAMETER

2019 ◽  
Vol 81 (4) ◽  
Author(s):  
Hari Prasetijo ◽  
Winasis Winasis ◽  
Priswanto Priswanto ◽  
Dadan Hermawan
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Single Phase ◽  
Air Gap ◽  
Wire Diameter ◽  
Terminal Phase ◽  
Magnetic Flux Density ◽  
Phase Voltage ◽  
Radial Flux

This study aims to observe the influence of the changing stator dimension on the air gap magnetic flux density (Bg) in the design of a single-phase radial flux permanent magnet generator (RFPMG). The changes in stator dimension were carried out by using three different wire diameters as stator wire, namely, AWG 14 (d = 1.63 mm), AWG 15 (d = 1.45 mm) and AWG 16 (d = 1.29 mm). The dimension of the width of the stator teeth (Wts) was fixed such that a larger stator wire diameter will require a larger stator outside diameter (Dso). By fixing the dimensions of the rotor, permanent magnet, air gap (lg) and stator inner diameter, the magnitude of the magnetic flux density in the air gap (Bg) can be determined. This flux density was used to calculate the phase back electromotive force (Eph). The terminal phase voltage (V∅) was determined after calculating the stator wire impedance (Z) with a constant current of 3.63 A. The study method was conducted by determining the design parameters, calculating the design variables, designing the generator dimensions using AutoCad and determining the magnetic flux density using FEMM simulation.  The results show that the magnetic flux density in the air gap and the phase back emf Eph slightly decrease with increasing stator dimension because of increasing reluctance. However, the voltage drop is more dominant when the stator coil wire diameter is smaller. Thus, a larger diameter of the stator wire would allow terminal phase voltage (V∅) to become slightly larger. With a stator wire diameter of 1.29, 1.45 and 1.63 mm, the impedance values of the stator wire (Z) were 9.52746, 9.23581 and 9.06421 Ω and the terminal phase voltages (V∅) were 220.73, 221.57 and 222.80 V, respectively. Increasing the power capacity (S) in the RFPMG design by increasing the diameter (d) of the stator wire will cause a significant increase in the percentage of the stator maximum current carrying capacity wire but the decrease in stator wire impedance is not significant. Thus, it will reduce the phase terminal voltage (V∅) from its nominal value.

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