scholarly journals Three-dimensional localization of a rotating magnetic dipole from the Fourier integrals of its magnetic flux density with acceleration data

AIP Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 025020
Author(s):  
A. Chiba ◽  
T. Nara
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Dipole ◽  
Three Dimensional ◽  
Magnetic Flux Density ◽  
Acceleration Data ◽  
Fourier Integrals

Magnetic phenomena

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Dipole ◽  
Electric Charge ◽  
Dipole Moments ◽  
Magnetic Flux Density

In this chapter we deal with a number of magnetic properties and their directional dependence: pyromagnetism, magnetic susceptibility, magnetoelectricity, and piezomagnetism. In the course of dealing with these properties, two new ideas are introduced: magnetic symmetry and axial tensors. Moving electric charge generates magnetic fields and magnetization. Macroscopically, an electric current i flowing in a coil of n turns per meter produces a magnetic field H = ni amperes/meter [A/m]. On the atomic scale, magnetization arises from unpaired electron spins and unbalanced electronic orbital motion. The weber [Wb] is the basic unit of magnetic charge m. The force between two magnetic charges m1 and m2 is where r is the separation distance and μ0 (=4π×10−7 H/m) is the permeability of vacuum. In a magnetic field H, magnetic charge experiences a force F = mH [N]. North and south poles (magnetic charges) separated by a distance r create magnetic dipole moments mr [Wb m]. Magnetic dipole moments provide a convenient way of picturing the atomistic origins arising from moving electric charge. Magnetization (I) is the magnetic dipole moment per unit volume and is expressed in units of Wb m/m3 = Wb/m2. The magnetic flux density (B = I + μ0H) is also in Wb/m2 and is analogous to the electric displacement D. All materials respond to magnetic fields, producing a magnetization I = χH, and a magnetic flux density B = μH where χ is the magnetic susceptibility and μ is the magnetic permeability. Both χ and μ are in henries/m (H/m). The permeability μ = χ + μ0 and is analogous to electric permittivity. χ and μ are sometimes expressed as dimensionless quantities (x ̅ and μ ̅ and ) like the dielectric constant, where = x ̅/μ0 and = μ ̅/μ0. Other magnetic properties will be defined later in the chapter. A schematic view of the submicroscopic origins of magnetic phenomena is presented in Fig. 14.1. Most materials are diamagnetic with only a weak magnetic response induced by an applied magnetic field.

The Influence of Stress Ratio on Changes in Magnetic Flux Density around Fatigue Crack Tips of Carbon Tool Steel

2011 ◽  
Vol 83 ◽  
pp. 210-215 ◽  
Author(s):  
Takashi Honda ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Hitonobu Koike ◽  
Justyna Rozwadowska ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Crack Growth ◽  
Flux Density ◽  
Tool Steel ◽  
Fatigue Cracks ◽  
Three Dimensional ◽  
Magnetic Flux Density ◽  
Hall Probe ◽  
Steel Component ◽  
Stress Ratios

Fatigue failure of steel occurs when cracks form in a component and continue to grow to a size large enough to cause fracture. In order to understand the strength of a steel component, it is important to locate these cracks. We developed a scanning Hall probe microscope (SHPM), equipped with GaAs film sensors to observe fatigue cracks at room temperature in air while they were growing. In our previous works [1,2], the correlation between crack growth and magnetic field in high carbon tool steels (JIS SKS93 and JIS SUJ2) were determined. We also reported the sensitivity of the SHPM equipped with a three-dimensional line-probe that was developed to decrease the sensor gaps. By using the line-probe sensor we succeeded to measure the magnetic flux density distributions in very close proximity to the specimen’s surface. However, in order to further understand the relation between magnetic flux density and crack growth, other materials, microstructures and fatigue test conditions should be evaluated. In the present work, we focus on the effect of stress ratios on the changes of the magnetic flux density in annealed carbon tool steel.

The Observation of Changes in the Magnetic Field due to the Crack Initiation under Different Stress Ratio Conditions

2011 ◽  
Vol 217-218 ◽  
pp. 1408-1413 ◽  
Author(s):  
Takashi Honda ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Justyna Rozwadowska ◽  
M. Uryu
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Crack Growth ◽  
Flux Density ◽  
Fatigue Cracks ◽  
Three Dimensional ◽  
Magnetic Flux Density ◽  
Hall Probe ◽  
Steel Component ◽  
Stress Ratios

Fatigue failure of steel occurs when cracks form in a component and continue to grow to a size large enough to cause fracture. In order to understand the strength of a steel component, it is important to locate these cracks. We developed a scanning Hall probe microscope (SHPM) equipped with GaAs films sensors and observed fatigue cracks at room temperature in air while they were growing. In our previous works, we determined the correlation between crack growth and magnetic field in high carbon tool steels (JIS SKS93 and JIS SUJ2). We also reported the sensitivity of the SHPM equipped with a three-dimensional line-probe that was developed to decrease the sensor gaps. By using the line-probe sensor we succeeded to measure the magnetic flux density distributions in very close proximity to the specimen’s surface. However, in order to further understand the relation between magnetic flux density and crack growth, other materials, microstructures and fatigue test conditions should be evaluated. In the present work, we focus on the effect of stress ratios on the changes of the magnetic flux density in annealed carbon tool steel.

Application of the Vector Finite Element Method to 3D Magnetohydrodynamics

2003 ◽  
Author(s):  
Masaaki Matsumoto ◽  
Takahiko Tanahashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Three Dimensional ◽  
Magnetic Flux Density ◽  
Shape Functions ◽  
Vector Finite Element Method ◽  
Vector Finite Element ◽  
Element Method

It is well known that the vector finite element method is one of the powerful tools for solving electromagnetic problems. The vector shape functions that are consist of the facet and the edge vector shape functions have a lot of characteristics. One of them is automatic conservation of the magnetic flux density in analyzing the Induction equations without iterative correction. In the present paper the vector finite element method is applied to the problems of magnetohydrodynamics. Three-dimensional natural convection in a cavity under a constant magnetic field is analyzed numerically using the GSMAC finite element method for flow field and temperature field and the vector finite element method for the Induction equations. The computational results are good agreement with those obtained using B method that is one of the iterative methods to satisfy the solenoidal condition for the magnetic flux density of the Induction equations.

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.

Observation of magnetic flux density around fatigue crack tips in bearing steel using an SHPM with a three-dimensional small-gap probe

2012 ◽  
Vol 39 ◽  
pp. 38-43 ◽  
Author(s):  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
Justyna Rozwadowska
Keyword(s):  
Fatigue Crack ◽  
Magnetic Flux ◽  
Flux Density ◽  
Three Dimensional ◽  
Bearing Steel ◽  
Magnetic Flux Density ◽  
Crack Tips

Study on Magnetic Field for Navigation of Articulated Needle

2012 ◽  
Vol 152-154 ◽  
pp. 952-957
Author(s):  
Hua Fang Huang ◽  
Yi Zhong Wang ◽  
Zong Guo Zhou ◽  
Yong Hua Chen
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Permanent Magnets ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Magnetic Flux Density ◽  
Variable Direction ◽  
The Magnetic Field ◽  
Three Dimensional Space

When the magnetic articulated needle is inserting, the magnetic field which can produce the magnetic force of variable direction is required in order to implement the magnetic navigation in three-dimensional space. The paper puts forward a method for generating three-dimensional magnetic field based on the rotaion and translation of multiple permanent magnets. In this method, multiple permanent magnets form a circumference array. Every permanent magnet can rotate around the spin axis of itself in the array plane and move along the direction vertical to the array plane. Thus, in the array center, a magnetic fied which can produce the uniform magnetic flux density is obtained. The direction of magnetic fied is controllable in three-dimensional space and the magnitude of magnetic flux density is variable in a certain range. The simulations by ANSYS verify the feasibility of the proposed method.

Monitoring Human Body Joint Rotations Based on Wearable Magnetic Strap Modules and the Jacobian Matrix of Magnetic Fields

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
José Baca ◽  
Michael Martinez
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Dipole ◽  
Human Body ◽  
Jacobian Matrix ◽  
Dipole Source ◽  
Magnetic Flux Density ◽  
Dipole Magnet ◽  
Magnetic Tracking ◽  
Body Joint

Abstract This work presents the development of a novel methodology in monitoring human body joint rotations based on magnetic tracking (localization). This project leverages the development of an experimental platform that can be used for healthcare within different domains such as senior care for evaluating rehabilitation therapies, the assessment of human body movements of stroke survivors, other patients with sensorimotor disorders, as well as, in space for monitoring astronauts during the execution of strength training and aerobic exercises. The main contribution is a novel magnetic tracking methodology that allows for the tracking of a magnetic dipole source in five degrees-of-freedom (5DOF) without the use of numerical methods. This approach is based on using the Jacobian matrix of the magnetic flux density from a dipole magnet. By using this approach, magnetometers that sense the magnetic flux density will be able to determine the position and orientation of a magnetic dipole source.

Sign in / Sign up

Export Citation Format

Share Document