Computational Modeling For Magnetic-Sensor-Based Three-Dimensional Visualization Of Microcracks

2001 ◽  
Vol 674 ◽  
Author(s):  
Leonid Muratov ◽  
David Lederman ◽  
Bernard R. Cooper
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Magnetic Tunnel Junction ◽  
Phase Segregation ◽  
Surface Region ◽  
Electrical Current ◽  
Element Analysis ◽  
Near Surface ◽  
Fast Recognition ◽  
The Magnetic Field

ABSTRACTThe presence of cracks, phase segregation, or even submicron-sized grain boundaries creates a disruption of the magnetic field response to an externally applied electrical current running through the material. These effects can be detected through the magnetic field leakage in the external near-surface region. Using a computer model of an array of magnetic tunnel junction detectors, magnetic “signatures” of various faults and/or material borders and domains have been calculated using finite element analysis and portrayed by icons. We have considered a number of typical cracks and flaws, of different dimensions and orientations, within the bulk of the component. The database of “signatures” thus generated allows fast recognition of faults and generation of their images in real time. Significant efforts have been made to provide an adequate three-dimensional visualization of the shape and distribution of microcracks, the magnetic field lines, and delineation of the position of the faults in relation to the surface.

Quantitative Research on Cracks in Pipe Based on Magnetic Field Response Method of Eddy Current Testing

2021 ◽  
Vol 36 (1) ◽  
pp. 99-107
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Li Tao
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Quantitative Research ◽  
Three Dimensional ◽  
Impedance Analysis ◽  
Eddy Current Testing ◽  
Element Analysis ◽  
Defect Parameter ◽  
Current Testing ◽  
The Magnetic Field

The quantitative evaluation of defects in eddy current testing is of great significance. Impedance analysis, as a traditional method, is adopted to determine defects in the conductor, however, it is not able to depict the shape, size and location of defects quantitatively. In order to obtain more obvious characteristic quantities and improve the ability of eddy current testing to detect defects, the study of cracks in metal pipes is carried out by utilizing the analysis method of three-dimensional magnetic field in present paper. The magnetic field components in the space near the crack are calculated numerically by using finite element analysis. The simulation results confirm that the monitoring of the crack change can be achieved by measuring the magnetic field at the arrangement positions. Besides, the quantitative relationships between the shape, length of the crack and the magnetic field components around the metal pipe are obtained. The results show that the axial and radial magnetic induction intensities are affected more significantly by the cross-section area of the crack. Bz demonstrates obvious advantages in analyzing quantitatively crack circumference length. Therefore, the response signal in the three-dimensional direction of the magnetic field gets to intuitively reflect the change of the defect parameter, which proves the effectiveness and practicability of this method.

scholarly journals Finite Element Analysis of Magnetic Field Exciter for Direct Testing of Magnetocaloric Materials’ Properties

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2792
Author(s):  
Wieslaw Lyskawinski ◽  
Wojciech Szelag ◽  
Cezary Jedryczka ◽  
Tomasz Tolinski
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Circuit ◽  
Homogeneous Magnetic Field ◽  
Element Analysis ◽  
Mcm Testing ◽  
Testing Region ◽  
Magnetocaloric Materials ◽  
Field Excitation ◽  
The Magnetic Field

The paper presents research on magnetic field exciters dedicated to testing magnetocaloric materials (MCMs) as well as used in the design process of magnetic refrigeration systems. An important element of the proposed test stand is the system of magnetic field excitation. It should provide a homogeneous magnetic field with a controllable value of its intensity in the MCM testing region. Several concepts of a magnetic circuit when designing the field exciters have been proposed and evaluated. In the MCM testing region of the proposed exciters, the magnetic field is controlled by changing the structure of the magnetic circuit. A precise 3D field model of electromagnetic phenomena has been developed in the professional finite element method (FEM) package and used to design and analyze the exciters. The obtained results of the calculations of the magnetic field distribution in the working area were compared with the results of the measurements carried out on the exciter prototype. The conclusions resulting from the conducted research are presented and discussed.

scholarly journals Site Specific Three-dimensional Structural Analysis in Tissues and Cells Using Automated DualBeam Slice &View

2007 ◽  
Vol 15 (2) ◽  
pp. 26-31 ◽  
Author(s):  
Ben Lich
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Surface Region ◽  
Dimensional Structure ◽  
Near Surface ◽  
Imaging Capability ◽  
Fluorescent Markers ◽  
Confocal And Electron Microscopy

DualBeam instruments that combine the imaging capability of scanning electron microscopy (SEM) with the cutting and deposition capability of a focused ion beam (FIB) provide biologists with a powerful tool for investigating three-dimensional structure with nanoscale (1 nm-100 nm) resolution. Ever since Van Leeuwenhoek used the first microscope to describe bacteria more than 300 years ago, microscopy has played a central role in scientists' efforts to understand biological systems. Light microscopy is generally limited to a useful resolution of about a micrometer. More recently the use of confocal and electron microscopy has enabled investigations at higher resolution. Used with fluorescent markers, confocal microscopy can detect and localize molecular scale features, but its imaging resolution is still limited. SEM is capable of nanometer resolution, but is limited to the near surface region of the sample.

scholarly journals Magnetic Field Structure of Star Forming Regions: VLBI Spectral Line Results

1984 ◽  
Vol 110 ◽  
pp. 333-334
Author(s):  
J.A. Garcia-Barreto ◽  
B. F. Burke ◽  
M. J. Reid ◽  
J. M. Moran ◽  
A. D. Haschick
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Aperture Synthesis ◽  
Stokes Parameters ◽  
Hii Region ◽  
Star Forming ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
The Magnetic Field ◽  
Synthesis Experiment

Magnetic fields play a major role in the general dynamics of astronomical phenomena and particularly in the process of star formation. The magnetic field strength in galactic molecular clouds is of the order of few tens of μG. On a smaller scale, OH masers exhibit fields of the order of mG and these can probably be taken as representative of the magnetic field in the dense regions surrounding protostars. The OH molecule has been shown to emit highly circular and linearly polarized radiation. That it was indeed the action of the magnetic field that would give rise to the highly polarized spectrum of OH has been shown by the VLBI observations of Zeeman pairs of the 1720 and 6035 MHz by Lo et. al. and Moran et. al. VLBI observations of W3 (OH) revealed that the OH emission was coming from numerous discrete locations and that all spots fell within the continuum contours of the compact HII region. The most detailed VLBI aperture synthesis experiment of the 1665 MHz emission from W3 (OH) was carried out by Reid et. al. who found several Zeeman pairs and a characteristic maser clump size of 30 mas. In this work, we report the results of a 5 station VLBI aperture synthesis experiment of the 1665 MHz OH emission from W3 (OH) with full polarization information. We produced VLBI synthesis maps of all Stokes parameters of 16 spectral features that showed elliptical polarization. The magnitude and direction of the magnetic field have been obtained by the detection of 7 Zeeman pairs. The three dimensional orientation of the magnetic field can be obtained, following the theoretical arguments of Goldreich et. al., from the observation of π and σ components.

scholarly journals Interpolation of externally-caused magnetic fields over large sparse arrays using Spherical Elementary Current Systems

2010 ◽  
Vol 28 (9) ◽  
pp. 1795-1805 ◽  
Author(s):  
S. A. McLay ◽  
C. D. Beggan
Keyword(s):  
Magnetic Field ◽  
External Field ◽  
Current System ◽  
Electrical Current ◽  
Ionospheric Currents ◽  
Large Area ◽  
Physically Based ◽  
Subsurface Current ◽  
Current Systems ◽  
The Magnetic Field

Abstract. A physically-based technique for interpolating external magnetic field disturbances across large spatial areas can be achieved with the Spherical Elementary Current System (SECS) method using data from ground-based magnetic observatories. The SECS method represents complex electrical current systems as a simple set of equivalent currents placed at a specific height in the ionosphere. The magnetic field recorded at observatories can be used to invert for the electrical currents, which can subsequently be employed to interpolate or extrapolate the magnetic field across a large area. We show that, in addition to the ionospheric currents, inverting for induced subsurface current systems can result in strong improvements to the estimate of the interpolated magnetic field. We investigate the application of the SECS method at mid- to high geomagnetic latitudes using a series of observatory networks to test the performance of the external field interpolation over large distances. We demonstrate that relatively few observatories are required to produce an estimate that is better than either assuming no external field change or interpolation using latitudinal weighting of data from two other observatories.

scholarly journals INCREASING THE EFFICIENCY OF MULTY-VARIANT CALCULATIONS OF ELECTROMAGNETIC FIELD DISTRIBUTION IN MATRIX OF A POLYGRADIENT SEPARATOR

2021 ◽  
Author(s):  
Jasim Mohmed Jasim Jasim ◽  
Iryna Shvedchykova ◽  
Igor Panasiuk ◽  
Julia Romanchenko ◽  
Inna Melkonova
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Magnetic Potential ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Air Gaps ◽  
Vector Magnetic Potential ◽  
Electromagnetic Separator ◽  
The Magnetic Field

An approach is proposed to carry out multivariate calculations of the magnetic field distribution in the working gaps of a plate polygradient matrix of an electromagnetic separator, based on a combination of the advantages of two- and three-dimensional computer modeling. Two-dimensional geometric models of computational domains are developed, which differ in the geometric dimensions of the plate matrix elements and working air gaps. To determine the vector magnetic potential at the boundaries of two-dimensional computational domains, a computational 3D experiment is carried out. For this, three variants of the electromagnetic separator are selected, which differ in the size of the working air gaps of the polygradient matrices. For them, three-dimensional computer models are built, the spatial distribution of the magnetic field in the working intervals of the electromagnetic separator matrix and the obtained numerical values of the vector magnetic potential at the boundaries of the computational domains are investigated. The determination of the values of the vector magnetic potential for all other models is carried out by interpolation. The obtained values of the vector magnetic potential are used to set the boundary conditions in a computational 2D experiment. An approach to the choice of a rational version of a lamellar matrix is substantiated, which provides a solution to the problem according to the criterion of the effective area of the working area. Using the method of simple enumeration, a variant of the structure of a polygradient matrix with rational geometric parameters is selected. The productivity of the electromagnetic separator with rational geometric parameters of the matrix increased by 3–5 % with the same efficiency of extraction of ferromagnetic inclusions in comparison with the basic version of the device

Experimental Research on the Magnetic Field Sensitive Polymeric Actuator

2011 ◽  
Vol 287-290 ◽  
pp. 603-607
Author(s):  
Chun Lin Xia ◽  
Yang Fang Wu ◽  
Qian Qian Lu
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Conversion ◽  
Experimental Research ◽  
Experimental Results ◽  
Deformation Characteristics ◽  
Analysis Software ◽  
Element Analysis ◽  
The Magnetic Field

Using domestic MFSP membrane as a medium of energy conversion, a kind of MFSP actuator was designed. The dedicated test equipment was constructed for experimental research, and the experimental results were given. The strip and circular MSFP membrane were analyzed qualitatively to obtain the deformation characteristics of membrane by finite element analysis software.

The magnetic field about a three-dimensional block neodymium magnet

2021 ◽  
Vol 62 ◽  
pp. 386-405
Author(s):  
Graham John Weir ◽  
George Chisholm ◽  
Jerome Leveneur
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Hard Disk Drives ◽  
Three Dimensional ◽  
Transverse Magnetic ◽  
Observation Point ◽  
Magnetization Direction ◽  
Potential Approach ◽  
Neodymium Magnet ◽  
The Magnetic Field

Neodymium magnets were independently discovered in 1984 by General Motors and Sumitomo. Today, they are the strongest type of permanent magnets commercially available. They are the most widely used industrial magnets with many applications, including in hard disk drives, cordless tools and magnetic fasteners. We use a vector potential approach, rather than the more usual magnetic potential approach, to derive the three-dimensional (3D) magnetic field for a neodymium magnet, assuming an idealized block geometry and uniform magnetization. For each field or observation point, the 3D solution involves 24 nondimensional quantities, arising from the eight vertex positions of the magnet and the three components of the magnetic field. The only unknown in the model is the value of magnetization, with all other model quantities defined in terms of field position and magnet location. The longitudinal magnetic field component in the direction of magnetization is bounded everywhere, but discontinuous across the magnet faces parallel to the magnetization direction. The transverse magnetic fields are logarithmically unbounded on approaching a vertex of the magnet.   doi:10.1017/S1446181120000097

Modeling and Designing an Intelligent Controller using Bond Graph for a Satellite Controlled by Magnetic Actuators

2012 ◽  
Vol 2 (1) ◽  
pp. 72-90 ◽  
Author(s):  
Majid Habibi ◽  
Alireza B. Novinzadeh
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Electrical Current ◽  
Bond Graph ◽  
Control Logic ◽  
State Equations ◽  
Magnetic Actuators ◽  
Advantages And Disadvantages ◽  
Aerospace Technology ◽  
Short Time

Satellite state control has always been an important topic in aerospace technology. Because it is required that when the satellite is stationary in orbit, it would be directed to a special object and this task should be performed in a situation where there isn’t access to the satellite. This task is performed using various technologies and one of these is the use of magnetic actuators. Magnetic actuators use mechanical torque that is resulted by interaction of electrical current of coils in the satellite and the earth’s magnetic field. The satellite is subjected to such disturbance torques, thus corrupting the direction of the satellite. This method has its advantages and disadvantages. Its drawback is that the magnetic torque is produced only perpendicular to the direction of the magnetic field and the axis of the coil. This paper models a satellite having magnetic actuators using bond graph, and finds out its state equations, and then constructs the control logic that is needed for its control. A model of three dimensional attitude maneuvers and magnetic systems using bond graph is described. The actuators are tuned using the method of particle swarm optimization (PSO). It is observed that using this method a small satellite reaches to the desired angle in a short time and becomes stationary.

Sign in / Sign up

Export Citation Format

Share Document