Three-dimensional Field Analysis Research Articles

Design of a compact gantry for carbon-ion beam therapy

This paper presents the design of a compact gantry that uses superconducting bending magnets (BMs), for use in carbon-ion beam therapy. The size of the gantry is comparable to those of existing gantries that are used for proton-beam therapy. The designed gantry provides point-to-parallel scanning over an area of $20\text{ }\text{ }\mathrm{cm}\ifmmode\times\else\texttimes\fi{}20\text{ }\text{ }\mathrm{cm}$ at the isocenter, and has rotationally invariant optics, which are enabled by quadrupole and dipole magnets together with a 90\ifmmode^\circ\else\textdegree\fi{} combined-function magnet with 18.6-cm bore radius. A 90\ifmmode^\circ\else\textdegree\fi{} BM accommodates large scanning angles; it also provides equal focusing in horizontal and vertical planes, and zero-integrated nonlinear fields to minimize beam distortion at the isocenter. Three-dimensional field analysis of the magnet, and particle-tracking simulation, validate the beam optics of the gantry and point-to-parallel scanning. The Taylor map and the Lie map are shown to be useful in the analysis of magnetic fields and in optimizing the coil windings.

Optimizing the Manufacturing Process of Twisted Cables: The Result Is an Increase in Conductivity and a Reduction in Weight

This article presents a method for optimizing the design parameters of a twisted conductor to increase a cable's conductivity and reduce its weight. This, in turn, can preserve the conductive material. An automated procedure for linking an optimization algorithm implemented in a MATLAB environment with the commercial finite-element code Abaqus for a three-dimensional field analysis was used. This study offers an original contribution to the field of cable design optimization, as it takes into account additional factors such as deformed geometry of the conductor, contact resistance, and the uneven distribution of resistivity within a filament.

Fractography Features of Fracture Surfaces of Glued Joints Made Using an Elastic Adhesive

This work is an attempt to use research results on the physical mesomechanics and quantitative fractography for the analysis of the fracture mechanisms of glued joints made using an elastic adhesive under shear loads. It is shown that this approach provides higher informativity of the fractographic analysis of fracture surfaces of glued joints. It is noted that, to increase the objectivity and accuracy of the fractographic evaluation, a quantitative analysis of three-dimensional fields of fracture surfaces must be performed.

Calculation of equivalent magnetic permeability of ferromagnetic materials for modeling of three-dimensional eddy current fields

The paper presents a method of calculating a constant value of magnetic permeability of ferromagnetic materials, equivalent to the basic magnetization curve by the criterion of real power. The proposed method makes it possible to use linear differential equations of the electromagnetic field in the analysis of three-dimensional fields of eddy currents in ferromagnetic materials, thus significantly reducing the calculation time. We propose a method of calculating the power of inductors using two-dimensional axisymmetric models. The scope of the proposed methods is limited to the case of placement of the inductor inside the ferromagnetic body.

Miniature Circuit Breaker Electromagnetic Release Simulation and Analysis

With the three-dimensional field analysis software Ansoft, we establish three-dimensional finite element model of the electromagnetic release, obtain the electromagnetic release static characteristics of electromagnetic force by simulation, and analyze the relationship between the electromagnetic force, the short-circuit current and the air gap size. By Analyzing the dynamic characteristics of moving iron core, different short-circuit currents influence on the velocity and displacement of the moving iron core was gained.

Influence of Eddy Current Effect on the Circuit Breaker Contact Mechanism Heat Loss

With the three-dimensional field analysis software Ansoft Maxwell 3D, the three-dimensional finite element model of the contacts pair is established. They belong to a kind of miniature circuit breaker. The simulation is carried out in the transient magnetic field. Under the condition with or without eddy current effect, we get the position and numerical solution of the contact mechanism heat loss under different short-circuit current.

Magnetic Field Measurement of Radial Sector FFAG Magnet for High-Brightness Muon Ring

The magnetic field of three scaled-radial-sector fixed field alternating gradient (FFAG)-magnets has been measured. The magnets have very large horizontal (1 m) and vertical (0.3 m) apertures to store muons and achieve phase rotation in an FFAG ring. The measurements results are compared to a three-dimensional field analysis using the TOSCA code; the generated magnetic field agrees satisfactorily with the TOSCA calculation in a range of 0.5\% for a large transversal (x-y-z) area. The three magnets show satisfactory performance for use in a ten-sector ring for a high-brightness muon source.

Electrical behaviour of a single crack in a conductor and exponential laws for conductivity in micro cracked solids

In this paper we analyse the electrical effects of the presence of cracks in solid conductors. We have studied such problematic from different points of view. Firstly, we have analytically evaluated the behaviour of the electrical field near a crack in an isotropic solid where a uniform current density is flowing, drawing a comparison with the behaviour of the well known stress and strain tensor fields in the analogue elastic problem. This computation has been made with a slit-crack (two-dimensional field analysis) and with a circular crack (three-dimensional field analysis). So, in order to quantify the spatial fluctuations of the local electric field around the crack we have numerically found the density of states for the field showing that it exhibit sharp peaks and abrupt changes in the slope at certain critical points which are analogous to van Hove singularities in the density of states for phonons and electrons in solids. Finally, we have performed a theoretical analysis of the conductivity of a microcracked solid. The distribution of cracks in the solid follows a given orientational distribution, which modify the conduction properties of the overall material. In particular, we have shown that the conductivity depends exponentially on the cracks density and on the size of each crack embedded in the medium.

Study of the Crystal Size Effect on Spatial Resolution in Three-Dimensional Measurement of Fine Electromagnetic Field Distribution by Optical Probing

The effect of crystal size on the spatial resolution of electro/magneto-optic probing measurement has been studied. This is especially important when one deals with three-dimensional field visualization over fine and complicated circuit patterns. Through experimental three-dimensional field analyses, the concept of the sensitive volume is introduced and has been proved to be an appropriate measure to define the three-dimensional spatial resolution. Based upon the reduction of the sensitive volume of a magneto-optic crystal, a magnetic field distribution over a 10-µm-class miniature circuit was precisely visualized in the x–z plane by the fiber edge magneto-optic probe using a 20-µm-thick crystal.

A design of the low-pass filter using the novel microstrip defected ground structure

A new defected ground structure (DGS) for the microstrip line is proposed in this paper. The proposed DGS unit structure can provide the bandgap characteristic in some frequency bands with only one or more unit lattices. The equivalent circuit for the proposed defected ground unit structure is derived by means of three-dimensional field analysis methods. The equivalent-circuit parameters are extracted by using a simple circuit analysis method. By employing the extracted parameters and circuit analysis theory, the bandgap effect for the provided defected ground unit structure can be explained. By using the derived and extracted equivalent circuit and parameters, the low-pass filters are designed and implemented. The experimental results show excellent agreement with theoretical results and the validity of the modeling method for the proposed defected ground unit structure.

The field analysis and simulation of a permanent-magnet bias-field device for magneto-optic recording

A method for the analysis of rotary permanent-magnet bias-field devices for magneto-optic recording applications is presented. The first part of the method entails a three-dimensional field analysis to determine the magnet dimensions that render a bias field of desired strength and uniformity across the medium. The second part of the method entails an analysis of the rotary dynamics of the magnet to determine the parameters that render a desired response time for field reversal. The theory is demonstrated via application to a practical device.

Modeling of magnetizing and core-loss currents in single-phase transformers with voltage harmonics for use in power flow

This paper presents two approaches for calculating the iron-core and copper losses of a 25 kVA single-phase pole transformer subjected to low-frequency voltage harmonics: an approximate calculation and a finite-element computer model. These methods can be applied to any transformer of similar construction by simply changing the input data, and they can be used for most other single-phase transformers with small modifications. The approximate method is a technique for calculating the change in iron-core losses which can be done without a computer. The finite element computer model performs a quasi three-dimensional field analysis on the iron-core region and calculates the flux density (B) and iron-core losses in each finite element, as well as the magnetizing and core-loss currents. The results of either method can be used at pre-processing for a (harmonic) power flow program.

Interactive computer program for coil geometry data base generation and manipulation

An interactive computer program GMAN has been developed to facilitate the generation and manipulation of coil geometry data bases required for three-dimensional magnetic field analyses. GMAN was designed specifically to be used in conjunction with the three-dimensional field analysis program EFFI developed at the Lawrence Livermore Laboratory. GMAN generates the coil geometry data elements from curves representing centerlines of windings. It can also be used to perform geometrical (symmetry) manipulations on the data elements. The design goal of the program is that it be versatile and easy to use so that the generation and modification of coil geometry data bases can be accomplished with a minimum amount of effort.

FORCES IN A SINGLE-SIDED LINEAR INDUCTION MOTOR

ABSTRACT This paper examines a number of the assumptions which are frequently made in the analysis of linear induction motors. Thrust and attractive force measurements made on a 2-m diameter test wheel fitted with an iron-backed aluminum sheet secondary and an arc-type primary are compared with results from three-dimensional field analyses. Among the effects which are examined in the paper are the curvature of the machine, the winding overhang, the finite permeability, conductivity and thickness of the backing iron.