bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal design of shoe shape to reduce the cogging torque of SPMSM of two type of magnet
Authors: Sim Da-Hee , Jang Jin-Seok , Jeong Jin-Chan , Kim Byung-Taek
Published: December 2018

This paper investigates optimal design of shoe shape so as to reduce cogging torque of variable-flux (surface permanent magnet synchronous motor) SPMSM using two type of magnets. First, it suggests numerical analysis method of cogging torque of motor organized by two types of magnet. With the numerical method, it designs shoe shape of stator that cogging torque is minimized. Finally, it verifies effectiveness of design using the finite-element analysis.
Vibration suppression of structure with electromagnetic shunt damping absorber
Authors: Xie Shilin , Li Peichao , Zhang Xinong , Yan Bo
Published: December 2018

The electromagnetic shunt damping absorber (EMSDA) is developed based on electromagnetic shunt damping mechanism. The governing equation of planar vibration system equipped with the EMSDA is derived. An optimization method is presented to determine the main working parameters of EMSDA on the basis of the built theoretical model. The objective function minimizing the response variance of system under white noise excitation is formulated. The particle swarm optimization algorithm is employed in optimization. The simulated and experimental studies on vibration control by use of EMSDA are conducted. The results show that the electromagnetic shunt damping absorber can attenuate significantly the structural vibration.
Robust and accurate crack reconstruction for eddy current non destructive testing
Authors: Li Min , Lowther David , Guimar\∼{a}es Frederico
Published: December 2018

Fast and accurate crack detection techniques are required for the eddy current non destructive testing, especially in the case where a large amount of environmental noise exists. This paper presents a robust inverse solution for accurate shape reconstruction of natural cracks. A robust formulation is employed to deal with the uncertainties caused by the noise in the eddy current testing signals. The proposed method is capable of producing more robust results than the conventional formulation in terms of the statistical analysis of the reconstruction tests.
Effect of defects on the complex permeability of soft magnetic composites
Authors: Xiao Ling , Sun Yanhua , Ding Chunhua , Yang Lihua , Cheng Wenjie , Yu Lie
Published: December 2018

To calculate the complex permeability of soft magnetic composites, two-dimensional analytical models with and without the defects were used for the complex case. The relation of the complex permeability with the frequency, component size ratio δ and inclusion particle size is deduced. The results show that the effect of the defects is even more pronounced for the complex permeability. The complex permeability is a function of the component size ratio δ and the size of the inclusion. Increasing the component size ratio δ causes a decrease of the complex permeability at the same frequency. With the increase of inclusion particle size when the component size ratio keeps constant 0.01, both of the real and imaginary parts increase. In addition, the theoretical method is tested by the experimental results, which can be used to design parameters before the experiment.
Study on the high frequency acoustic noise and vibration of a pan generated by an IH cooker
Authors: Yonemori Hironobu , Fujiwara Akihiro , Maruyama Ryo , Kobayashi Miki
Published: December 2018

This paper discusses high frequency acoustic noise generated by an IH cooker. Mechanism of the high frequency acoustic noise generation is clarified by experimental study. Recently, influence of the electromagnetic wave on the human body is worried. They symptoms some users of home electronic appliances feel are headache and nausea. There is a report that other users who are using IH cooking heater also feel these symptoms. We have discovered that the high frequency acoustic noise, which is generated from an IH cooker, indicates strong-level sound pressure. High frequency strong acoustic noise must not be ignored, because its danger on our health is reported scientifically and medical standpoints. Then, it becomes necessary to examine the suppressing method of high frequency acoustic noise. In this paper, generating mechanism of the high frequency (20 kHz ∼) acoustic noise is clarified by the experiments.
Design of connector for measurements in high frequency on anchor rods
Authors: Novo L.R.G.S.L. , De Melo M.T. , De Oliveira M.R.T. , Bezerra J.M.B. , De Medeiros L.H.A. , Aquino R.R.B.
Published: December 2018

Companies of power transmission lines and telecommunications need to know the condition of their structures. However, there are ones which are buried or encased in concrete below-ground. Nondestructive techniques are essentials to investigate the condition of the rods used to anchor guy cables in guyed towers. A connector and a matching circuit have been designed to allow a network analyzer to apply and receive high frequency signals on these rods and, furthermore, to be able to identify corrosion or holes on an anchor rod using a promising nondestructive technique. High frequency analysis have been done on the results provided by simulations and experimental tests through the reflected signals that come in the input port of the connector and matching circuit. The high frequency connector, named CHAAF, was fabricated and tested.
Analytic 3-D eddy current model of a finite width conductive plate including edge-effects
Authors: Paul Subhra , Bird Jonathan Z.
Published: December 2018

This paper presents a new eddy current modeling approach in which the edge field contribution for a finite width conducting plate is accounted for. The 3-D steady-state analytic eddy current model accounts for the source field contributions from oscillatory as well as translational velocity motional effects. The paper discusses the modeling inaccuracies caused by neglecting the source field contributions on the edges of the conductive plate. The new modeling approach is validated by comparing the analytic calculations with a 3-D steady-state finite element analysis model.
Two-layer sloshing of magnetic fluid and silicone oil under horizontal magnetic field
Authors: Ishiyama Takayoshi , Kaneko Shunsuke , Takemoto Shin-ichiro , Sawada Tatsuo
Published: December 2018

This study investigates the behavior of two-layer sloshing using a magnetic fluid and silicone oil. To obtain basic relations, a linear theory is employed. After obtaining those relations, theoretical values of free-surface displacement, resonant frequency, and resonant pressure amplitude are compared with experimental results. Experimental data are obtained using a laser sensor and four pressure transducers. Free-surface displacement is measured by the laser sensor. Resonant frequency is measured by both the laser sensor and pressure transducers. Resonant pressure amplitude is recorded by the pressure transducers. The results demonstrate that the theory employed in this study is effective as a first estimation of two-layer sloshing. However, to describe the behavior of a two-layer magnetic fluid sloshing more precisely, a nonlinear analysis that considers magnetic force is necessary.
An improved multi-objective cross-entropy method for inverse problems
Authors: An Siguang , Yang Shiyou , Wu Xiushan
Published: December 2018

An improved vector cross-entropy (CE) method is proposed to provide a potential candidate for solving multi-objective inverse problems with a large number of variables. To balance the exploitation and exploration searches, the whole iterative process is divided into two phases: diversification and intensification phases. Different parameter evolutionary mechanisms of the probability density functions (pdfs) are proposed for different phases. To speed up the convergence rate, a dynamic evolutionary mechanism is proposed. To enhance the diversity of the sampling points, a mutation manipulation is introduced. The ZDT test functions and a high frequency inverse problem are used as the case studies to testify the effectiveness and efficiency of the proposed method.
Two-dimensional magnetic susceptibility mapping of long objects by magnetic resonance imaging
Authors: Zhu Haitao , Demachi Kazuyuki , Wu Wenjing , Sekino Masaki
Published: December 2018

Magnetic susceptibility is the inherent property of materials. Magnetic resonance imaging as a kind of non-invasive testing technique may measure the magnetic field distortion induced by the imaging object and consequently calculate its magnetic susceptibility distribution. Conventionally, magnetic susceptibility mapping is performed in three-dimensional mode with the requirement of multi-slice scanning. In the condition of long objects that have uniform distribution along one direction, two-dimensional phase image of the cross section might be enough to estimate the susceptibility. In this study, we adjust susceptibility mapping algorithm into a two-dimensional mode and evaluate the possibility of using a single-slice image to estimate the magnetic susceptibility. Simulation was performed to validate the algorithm in both ideal and noise-imposed conditions. MRI experiment was performed by using copper, graphite and iron oxide at different concentrations. The results suggest that it is possible to measure the susceptibility of a long object by a two-dimensional image.
Development of a flexible and stiffness changeable mechanism for NOTES
Authors: Zhao Ruzhen , Zhao Shuang , Luo Yun
Published: December 2018

NOTES (natural orifice translumenal endoscopic surgery) allows for exceedingly minimally invasive surgery but has high requirement for dexterity, force capabilities and safety of tools. Researchers have proposed some flexible instrument used in surgeries. However, little work has considered the safety problem of the instrument to human tissues due to the absence of controllable flexibility and insufficient force capabilities. This paper presents a design of a flexible and stiffness changeable mechanism which can serve as a tunnel for NOTES tools. Furthermore, the flexible and the stiffness changeable properties are evaluated by FEM analysis.
Design of a constant-force component using superelastic SMA
Authors: Wang Minghui , Zhou Ying , Wu Yue , Gan Yun , Zhao Ruzhen , Luo Yun
Published: December 2018

Soft tissue injuries remain as problems in the application of clamping devices due to overload. Clamping devices with constant force or pressure is desired to solve the problem. This paper proposed a C-shaped component using superelastic shape memory alloy (SMA) sheet to realize constant force clamping. Optimization design of the component was carried out with computational simulation. Numerical results show that approximately constant force can be obtained by varying the initial shape, the end width and the end thickness of the SMA sheet.
Sensorless field oriented control using back-EMF and flux observer for a surface mounted permanent magnet synchronous motor
Authors: An Lu , Franck David , Hameyer Kay
Published: December 2018

This paper proposes a Sensorless Field Oriented Control for surface mounted permanent magnet synchronous motor combining two approaches for different rotor speed ranges. The active flux observer is applied at low speed and combined with a back-EMF observer at high speed. This combination allows for an improvement of the rotor position estimation for a large speed range and is therefore resulting in a higher stability of the sensorless control scheme when compared to the conventional back EMF method. The presented approach is discussed based on simulations.
A comparative numerical study of repulsive forces for stabilizing a rectangular aluminum plate between ac induction type and ac ampere type magnetic levitation methods
Authors: Ohji Takahisa , Kato Fuyuki , Amei Kenji , Sakui Masaaki
Published: December 2018

This paper deals with the comparative numerical study of repulsive forces acting on a rectangular aluminum plate by using two methods of magnetic levitation (maglev) – conventional ac induction type maglev and ac ampere type maglev proposed by the authors. We made up three-dimensional finite element models for these maglev methods and evaluated calculated repulsive forces in each axis of orthogonal coordinates. As a result, we achieved computer-aided visualization of eddy current in a levitated aluminum plate and magnetic flux around the plate. In addition, we found that the stability in the guidance direction is fully maintained in both methods, and the repelling force of ac ampere type maglev in the conveyance direction decrease compared to that of ac induction type maglev.
Reliability evaluation of pipe thickness measurement by electromagnetic acoustic transducer
Authors: Nakamoto Hiroyuki , Kojima Fumio , Tabata Hiroki , Kosaka Daigo
Published: December 2018

Non-destructive inspection is an important technique in the maintenance of plants and factories. It is necessary to appropriately evaluate the reliability of non-destructive inspection techniques. This study focuses on a reliability evaluation method for nondestructive inspections. The reliability method uses the probability of detection (POD) as a metric. A POD function is determined based on the thicknesses, signal responses, and a decision threshold for all pipe-wall measurements, and can be reasonably modeled by the cumulative log normal distribution function. In this study, the POD is applied to reliability evaluations of an electromagnetic acoustic transducer (EMAT), which is a non-destructive inspection device. Using the results of experimental measurements, we confirm that the POD can evaluate the reliabilities of EMATs that have different specifications.
Triple-band circular patch antenna using rising sun shaped metamaterial structure
Authors: Raval Falguni , Kosta Y.P. , Joshi Harshita
Published: December 2018

This paper discusses a triple-band microstrip circular antenna using rising sun shaped structure embedded in the substrate of patch antenna. The proposed design is based on the metamaterial property of rising sun shaped structure. The proposed antenna shows good performance at all resonant frequencies. The rising sun structure in substrate makes a major contribution to the first and second operating bands, while it has a minor effect on the third operating band. The proposed antenna is compared with the conventional antenna. This antenna has a high gain at all working frequencies. The simulation results are analyzed and compared with the measured results, which shows that there is a good agreement between them.
Design of antipodal Vivaldi antenna with better performances for ultra wideband applications
Authors: Yang Xiao Qing , Zhai Ying Ya , Xu Chen , Jia Guo Zhu
Published: December 2018

Two different antipodal Vivaldi antennas design with better performances are proposed. The one is a small antipodal Vivaldi antenna for a 4.1–20 GHz frequency range, and its dimension is only 34 × 50 mm ^{2} . Another proposed high gain antenna can achieve the maximum gain of 15.2 dBi within its operating band. Measured results of the manufactured antipodal Vivaldi antennas are in good agreement with the simulated ones. Besides the |S_{11}| , far field radiation pattern, current distribution, phase, gain, and group delay which are important parameters of impulse distortion in ultra-wide band antenna are well analyzed. All results show that the proposed antipodal Vivaldi antennas have better performances and they are well suited for ultra-wide band communications.
Minimizing design criterion and sensitivity: Cost-effective evolutionary approach with application in mechatronics
Authors: Di Barba P. , Savini A. , Wiak S.
Published: December 2018

Optimizing against sensitivity is a major issue in optimal design of electromagnetic devices. In the paper, the optimal shape design problem against sensitivity is formulated in terms of Paretian optimality, trading off design criterion and sensitivity with respect to large-scale variations in the design space; a cost-effective evaluation of sensitivity, based on evolutionary computing, is proposed. The design optimization of a magnetic MEMS is considered as the case study.
Topology design method of flux barrier in IPM motor by means of genetic algorithm implemented by multistep procedure
Authors: Okamoto Yoshifumi , Tominaga Yusuke , Wakao Shinji , Sato Shuji
Published: December 2018

This study derives a high performance flux barrier for an interior permanent magnet (IPM) motor using binary-based topology optimization (TO). TO has a higher degree of optimization than size or shape optimization. An IPM motor has many design parameters including the current phase angle, core shape of rotor and stator, and magnet position and shape. The flux barrier in an IPM motor plays a particularly important role, influencing several characteristics. We apply TO, using a multistep genetic algorithm, to the rotor core in order to determine a flux barrier with the highest torque performance.
Evaluation of magnitude- and phase-correct unit-force transfer functions for the structural description of electrical machines
Authors: Schröder Michael , Franck David , Hameyer Kay
Published: December 2018

The structural dynamic simulation of electrical machines is an appropriate tool to improve electrical machines in an early design stage, in consideration of their acoustic and vibration properties. In order to reduce the calculation effort, a time efficient method is desirable. Unit-force transfer functions describe the linear behavior of the structure when it is excited with unit-force waves in the machine's air gap. In this paper, magnitude- and phase-correct transfer functions are simulated numerically for an exemplary machine and then verified by measurements. With those transfer functions, the structural response of the machine can be calculated fast for different operating points.
Vibration analysis of permanent magnet motor with concentrated windings
Authors: Witczak Pawel , Swiniarski Jacek
Published: December 2018

Magnetic vibration forces in PM motor were obtained by finite elements analysis of 2D magnetic field followed by 2D Fourier transform. The dominated modal components of force spectrum were applied in 3D structural model preserving their rotational character.
Considerations of uncertainty in robust optimisation of electromagnetic devices
Authors: Xiao Song , Li Yinjiang , Rotaru Mihai , Sykulski Jan K.
Published: December 2018

Due to unavoidable uncertainties related to material properties and manufacturing processes, the robustness of the optimal solution must be considered when designing electromagnetic devices. In this paper, the worst-case optimisation (WCO) and the worst-vertex-based WCO are proposed to evaluate the robustness of both performance and constraints under uncertainty. To reduce computing times when searching for the robust solution a predicted objective function is used, obtained with the help of a kriging algorithm which explores the searching space using the concept of rewards. Finally, to avoid some of the shortcomings of WCO, the concept of average performance evaluation is developed.
The multiple objective optimization of high-speed rotor supported by magnetic bearing in BLDCM
Authors: Yuan Qian , Han Bangcheng , Dong Baotian
Published: December 2018

In order to find an algorithm to get a better optimization result of high-speed rotor supported by magnetic bearing in BLDCM, we presented a multiple objective optimization results which included three algorithms' in this paper. They are the local Sequential Quadratic Program (SQP) algorithm, the global Genetic Algorithm (GA) and the combined optimization strategy algorithm which combines GA and SQP. The parametric optimization model of a 100 kW BLDCM supported by magnetic bearings was constituted with software ANSYS and an effective connection between software ANSYS and iSIGHT was used to execute the whole optimization process. To insure the best performance, mass and strength were chosen as the optimization goals, meanwhile, the static strength, dynamic modal, shape and magnetic force of the rotor subassembly were used as the main constrains. Six main dimensions of the subassembly were optimized. The optimization results indicated that the GA can get a higher optimization precision than the other two algorithms and the SQP was not effective in the optimization of magnetic suspended motor rotor subassembly. The GA's optimization result made the mass decrease 7.62 percent with the safe factor is 3.15. The 100 kW BLDCM supported by magnetic bearings was designed and fabricated; the multiple objective optimization results were verified by the prototype.
Simulation and analysis of a novel wideband microwave coaxial reactor
Authors: Lin X.J. , Huang K.M. , Yang Y.
Published: December 2018

For the study of microwave chemistry, it is necessary to develop a reactor with small-size and wide operating frequency band. This paper presents a novel microwave coaxial reactor. Its main part is a coaxial cavity, and the input end is a coaxial port filled with PTFE, and the other end is a short circuit terminal. Two orifices which are designed as cut-off waveguides for microwave are attached to the cavity as passageway of sample solutions, so the reactor can treat the samples continuously. The distributions of electromagnetic field and temperature of this novel microwave coaxial reactor used for heating edible vegetable oil at 915 MHz and 2450 MHz are simulated with finite-element method multi-fields coupling analysis. It is easy to find out that this novel microwave coaxial reactor could work properly over a wide frequency band. Also, the operating frequency could be chosen over a wide frequency band to get the optimal reaction effect to meet the requirements of experiments.
Simulation and analysis on electro-magnetic- thermal coupling of solenoid GDI injector
Authors: Cheng Qiang , Zhang Zhen-Dong , Guo Hui , Xie Nai-Liu
Published: December 2018

The GDI (Gasoline Direct Injection) injector is influenced by electro-magnetic-thermal coupling, and has strong nonlinearity and coupling. Temperature rise greatly impacts the performance of the GDI injector and makes the ECU of the engine difficult to control fuel injection quantity accurately. According to the coupling relationship of electric, magnetic and thermal subsystems of the GDI injector, the physical model of coupled process was established. The energy loss and transformation of the GDI injector in work process was explored, and revealed that the energy loss in electromagnetic conversion was a key factor to cause the GDI injector temperature rise. The energy loss coming from electromagnetic conversion was regarded as heat source. The temperature field of the GDI injector contains heat conduction and thermal radiation was analyzed based on the finite element theories. By using the ANSYS software to simulate multiple physical fields of the GDI injector, and then experiment method to verify the simulation results, distribution characteristics of temperature field and variations of temperature rise effect on the performance of the GDI injector was analyzed. The results show that, higher temperature rise is concentrated on coil and core part and with the higher temperature rise the response time of the GDI injector get longer, the fuel injection quantity becomes less. The value and pulse width of the holding current I have great impact on the GDI injector performance and temperature rise.
Long-range inspection of a pipe with a bend using microwaves
Authors: Uoshita Shoya , Sasaki Kota , Katagiri Takuya , Yusa Noritaka , Hashizume Hidetoshi
Published: December 2018

This study evaluated the effect of bends on the long-range nondestructive testing inspection of pipe surfaces based on microwaves propagating inside the pipe. Three-dimensional finite element simulations were conducted to reveal electromagnetic fields at bends with a diameter of 23 mm and various radii of curvature when microwaves were emitted into a pipe in the TM01 mode that had been mainly used in earlier studies. The simulations revealed that the effect of the bend on the microwaves is not significant when the ratio of curvature is larger than approximately 2, whereas in general a bend reflects a part of microwaves and causes non-TM01 modes. Subsequent experimental verifications, which used a pipe with a total length of approximately 4 m and a 90-degree or 180-degree bend, confirmed clear reflections due to artificial wall thinning in spite of the presence of the bend.
A thickness-shear high voltage piezoelectric transformer
Authors: Yang J.S. , Zhang W.
Published: December 2018

A high voltage piezoelectric transformer working with thickness-shear modes is proposed. For the analysis of the proposed transformer, one-dimensional equations for coupled thickness-shear and flexural motions of a piezoelectric beam with rectangular cross section are employed and are simplified by thickness-shear long wave approximation. Free vibration frequency equation and modes are obtained which exhibit the mechanism of the transformer. The analysis is for piezoelectric materials of arbitrary anisotropy. A ceramic thickness-shear transformer is discussed as an example.
Mesoscopic simulation of electromagnetic phenomena in BSCCO single crystal under AC magnetic field
Authors: Demachi Kazuyuki , Takase Kentaro , Sugiyama Hirotaka , Miya Kenzo
Published: December 2018

In this study the Fluxoid Dynamics (FD) method was developed to simulate the mesoscopic behavior of the fluxoids in Bi2212 single crystal. This method is based on a combination of two concepts; the Molecular Dynamics (MD) and Ginzburg-Landau (G-L) theory. The aim of this study is to predict the macroscopic electromagnetic phenomena by simulating the mesoscopic behavior of many fluxoids. The predicted results of the dependence of the increase of critical current density upon the dose of heavy ion irradiation was compared with the experimental ones.
Shape memory superconductor
Authors: Hagiwara Naotada , Yabe Hiromasa , Oguri Kazuya , Asaka Takashi , Suzuki Tsunenori , Nishi Yoshitake
Published: December 2018

In order to obtain strong power of shape memory effects for application as an actuator, the volume change on softening of the high T_c YBa _2 Cu _3 O _{6.9} superconductor was studied. A softening induced volume change was found from 90 K to 160 K.
Low deforming induction heating of locomotive wheel: Coupled electromagnetic, thermal and mechanical simulation
Authors: Gontarowsky Pawel P. , Pantelyat Michael G.
Published: December 2018

The coupled electromagnetic, thermal and mechanical simulation for induction heating of railroad wheel is described. The developed mathematical models, numerical algorithms and software are intended for finite element analysis of interactive electromagnetic, thermal and mechanical processes in treated wheels. The problems are solved in axisymmetrical formulation. The aim of simulation is the definition of rational technological conditions of induction heating without using of full-scale experiment.
Dynamic magnetic hysteresis modelling using Elman recurrent neural network
Authors: Saghafifar Mahmoud , Kundu Anjan , Nafalski Andrew
Published: December 2018

Dynamic magnetic hysteresis modelling is of crucial importance in determining the electromagnetic behaviour of magnetic cores. Among the different models of magnetic hysteresis, Preisach model is one of the more commonly applied. The dynamic Preisach model is a generalisation of the static Preisach model, and is obtained by adding the rate of change of the output variable, which makes the numerical implementation more complex.

Since dynamic hysteresis models require mapping of time dependent sequences, a feature available in some neural networks, in this paper the application of recurrent neural networks to model dynamic hysteresis was investigated. An Elman neural network was selected to test the concept. The network was trained with a set of measured dynamic data and was tested with another set of experimental data, showing acceptable accuracy.
Analysis of thermal critical curves in temperature and time dependent Preisach type models
Authors: Borcia I.D. , Spinu L. , Stancu Al.
Published: December 2018

The shape and the movement of the critical curves in the Preisach plane are investigated using the numerical solution of master equation with variable magnetic field and temperature. It is shown that the shape of the thermal critical curve is a curve line. The movement of the thermal boundaries is simulated in magnetization processes with constant or variable field. Using this model we can explain the dependence of the coercivity on the variation rate of the magnetic field.
Flaw detection using dc magnetic field measurement
Authors: Sebestyén I. , Pávó J.
Published: December 2018

Detection of internal flaws in conducting materials with considerable thickness is difficult using eddy current tests. This paper presents an alternative method, which uses dc magnetic field excited by the current impressed across the conducting material. In this case the internal flaws give rise perturbations of current flow and consequently the magnetic field is also changed. Perturbations in the magnetic field can be detected by dc (direct current) sensors such as magnetoresistive or Fluxset sensors. In this work numerically performed experiments are presented to recover flaws at the interfaces of metal parts jointed at high temperature by high intensity pressure.
Vibration analysis and control of reciprocating air-compressors
Authors: Rens J. , Clark R.E. , Howe D.
Published: December 2018

Reciprocating air-compressors inherently generate high vibrational forces, which are transmitted to supporting structures and may result in a high level of acoustic noise. In many applications, this cannot be tolerated, and, therefore, an effective means of controlling the transmitted vibration energy between a compressor and its surroundings must be employed. In this paper, an analysis of a typical reciprocating actuator is described, and an active method for suppressing the transmission of vibrations is proposed.
Combining response surfaces and evolutionary strategies for multiobjective pareto-optimization in electromagnetics
Authors: Bramanti A. , Di Barba P. , Farina M. , Savini A.
Published: December 2018

The reduction of computational cost of evolutionary multiobjective Pareto-optimization algorithms is necessary when time-consuming objective functions evaluation is required. To this end neural network interpolation techniques are used for objective response surface building; evolutionary multiobjective Pareto-optimization is then performed on interpolated functions. Both analytical multiobjective test problems and numerical electromagnetic design problems are considered; the study of Pareto optimal front interpolation accuracy versus neural network training cost is performed.
A Study of planar inductor
Authors: Naruta T. , Endo H. , Hayano S. , Saito Y.
Published: December 2018

In order to design an optimal planar inductor, this paper carries out several axisymmetrical magnetic field simulations fully taking the magnetic hysteretic properties of ferromagnetic core materials as well as open boundary condition into account. Finite element method is applied to evaluating the magnetic fields, reactive and dissipative energies in a planar inductor. Because of the nature of magnetic fields, it is essentially taken into account the open boundary effects to evaluate the exact characteristics of planar inductor. Since the finite elements is one of the methodologies to solving for the partial differential equations, and then it has been difficult to take the open boundary effects into account. However, this paper removes this difficulty by employing the strategic dual image (SDI, in short) method [1,2]. Another difficulty is caused by the hysteretic magnetization characteristics of magnetic core materials. Applying the Chua type magnetization model to represent the hysteretic property also removes this difficulty. As a result, it is revealed that the frequency characteristic of core magnetic materials as well as shape dominate major characteristics of the magnetic fields, reactive and dissipative energies in the inductors.
Reconstruction of planar magnetic charge distribution
Authors: Igarashi Hajime , Kost Arnulf , Honma Toshihisa
Published: December 2018

This paper discusses reconstruction of magnetic charge distribution on a planar region for non-destructive evaluation. Reconstruction is performed by using the magnetic fields measured on a plane above the charge region as input data. The present method needs only one matrix inversion whose computational time is expected to be shorter than the method based on optimization processes. It is shown that the reconstruction is successful when the unknown vector is appropriately regularized in order that the corresponding singular vectors become smooth. The L-curve method works well for determination of the value of the regularization parameter.
Tilting control of railway vehicle using electric actuators
Authors: Yoshida Hidehisa , Nagai Masao
Published: December 2018

When a railway vehicle passes through a curve, reducing the lateral acceleration affecting its passengers is important in order to improve the ride comfort. Tilting control by feedback, which can maintain the vehicle inclination close to a desired value, is examined in this paper; reduction of car body vibration is also anticipated with this control. Specifically, the curvature is obtained by collecting data in real time from the car body traveling through a curve, and this information is utilized in the proposed tilting control method. The effects of the control scheme are verified by computer simulation using a dynamic model and experiment with model equipment.
Echo pattern width of a conducting strip loaded with a lossy dielectric layer
Authors: Hamid A.-K. , Hussein M.I.
Published: December 2018

The problem of electromagnetic wave scattering by a conducting strip loaded with a lossy dielectric layer is analyzed using elliptic waves expressed in terms of complex Mathieu functions. Numerical results are obtained for the scattered field in the far zone for different axial ratios, lossy dielectric constants, and angles of incidence. The numerical results show a significant change in backscattering echo due to the presence of a lossy dielectric coating.
Adapted eddy current excitation using a dual gradiometric coil system
Authors: Gierelt Gertrud , Allweins Kai , von Kreutzbruck Marc
Published: December 2018

Due to the skin effect, the induced eddy current (EC) density at the sample's surface is higher than at deeper levels. Thus currents flowing close to the surface generate most of the background signals caused by the sample's own components. One way of minimizing those EC interference is to reduce the surface currents and enhance the current density at the depth in which defects can occur. Unfortunately, magnetic fields cannot be focused to one point in the way rays of light can be concentrated in optics. Magnetic fields are always divergent – as quantified by Maxwell's Equations. To tackle this problem we superimposed two different excitation fields generated by a dual gradiometric coil excitation scheme (DGC). It consists of two double-D coils. Both double-D coils are applied with the same frequency but driven with two different excitation currents ( J_1 , J_2 ) and phase shifts (φ _1 , φ _2 ). In addition we implemented a sensitive magnetometer in our eddy current testing system to measure very thick structures of the Airbus A-380. We report on FEM simulations and EC-measurements using the dual gradiometric coil excitation scheme to detect deep lying defects.
Droplet production from a capillary jet of magnetic fluid under a magnetic field
Authors: Sudo Seiichi , Ise Kazutaka
Published: December 2018

This paper is concerned with the development of the vibration system for the drop formation of magnetic fluid. The breakup of magnetic fluid jet generated by the longitudinal vibration of the permanent magnet-magnetic fluid system is studied experimentally with the three-dimensional motion analysis system. The detailed processes of the droplet production, capillary jet breakup, and jet formation are revealed.
Lumped low-order time-domain model of eddy current effects in laminated cores
Authors: Gyselinck Johan , Dular Patrick
Published: December 2018

The authors present a novel lumped model for laminated cores considering the 1D eddy current problem in a conducting ferromagnetic lamination. The model is based on a polynomial spatial expansion of the induction and the magnetic field throughout the thickness of the lamination, of order n and n+2 respectively, such that the governing partial differential equation is satisfied (for any n≥0). The magnetic constitutive law is weakly imposed, leading to a system of 1+n/2 nonlinear differential equations. The method is elaborated and validated for both the linear and the nonlinear case. A fast convergence towards the exact solution(n=∞) is observed when increasing n.
3D FEM of magnetostriction phenomena using coupled constitutive laws
Authors: Azoum Karim , Besbes Mondher , Bouillault Frédéric
Published: December 2018

The aim of this work is to present a three-dimensional generalized finite element modelling of magnetostrictive materials including direct and inverse effects through strongly coupled magnetic and elastic behaviours. Emphasis is put on adapted constitutive laws that incorporate explicitly the physical coupling between magnetic and mechanical magnitudes. We used a variational formulation in terms of magnetic vector potential circulation and displacement. The studied example is composed of a solenoid with a magnetostrictive core where a three dimensional analysis is performed.
An advanced processing method of ECT images based on defect-orientations
Authors: Taniguchi Tetsuki , Nakamura Kazunori , Yamada Sotoshi , Iwahara Masayoshi
Published: December 2018

This paper presents a novel procedure for eddy-current image processing based on defect-orientations. First, nonlinear filtering technique is used to eliminate the noise and offset component in the ECT signals keeping the shape of defect-origined signals. Then the direction finding and the pattern matching methods are carried out to find the position of the defect with a specific direction. Based on the derived information, the classification of defects and image synthesis are carried out. Through an application to images derived from samples having defects in various orientations, the effectiveness of the proposed method is verified.
Advanced MFLT for detecting far side defects in a welding part of an austenitic stainless steel plate
Authors: Chen Zhenmao , Yusa Noritaka , Miya Kenzo , Tanahashi Akira , Sakai Kazuo , Chigusa Naoki
Published: December 2018

In this paper an advanced MFLT method is proposed for detecting far side defects in a welding part of a thick stainless steel plate based on the measurement of the remanent magnetic field. The method consists of a double yoke magnetizer, high frequency demagnetization procedure and an inverse analysis scheme. The performance of the proposed method is investigated through numerical simulations and experiments. The results show that a far side defect in a plate as thick as 20 mm is possibly to be detected by using the proposed strategy.
Magnetic levitation control with real-time and fewer sensors using finite element method
Authors: Tanaka A. , Torii S.
Published: December 2018

This paper proposes a novel scheme of thin steel plate levitation, which uses real-time finite elements calculation. The number of gap sensors is reduced using the proposed method. The simulation of the vibration, which occurs in the steel plate, shows the possibility of real-time installation. Then, the estimated gap length of the electromagnet in the one-end fixed system is compared to the experimental results. In spite of the difference in amplitude, the correspondence of the phase of the vibration clearly shows the possibility and the feasibility of the proposed system. Then, the experiment of the vibration control showed that a position could be estimated with FEM.
Measurement of two-dimensional vector magnetic properties on frequency dependence of electrical steel sheet
Authors: Urata Shinya , Shimoji Hiroyasu , Todaka Takashi , Enokizono Masato
Published: December 2018

This paper presents measured results of the two-dimensional vector magnetic properties in electrical steel sheets under high frequency excitation conditions. The relationship among the maximum flux density, the magnetizing direction, the exciting frequency, the axis ratio of the rotating flux density(the ratio of the maximum flux density and the minimum flux density), and the iron loss is clarified. The results obtained from the non-oriented electrical steel sheet (35A550) and for the grain-oriented electrical steel sheet (35G155) are compared in this paper.
Pre-martensitic phenomena in a near stoichiometric Ni_2MnGa Polycrystalline alloy
Authors: Sánchez-Alarcos V. , Pérez-Landazábal J.I. , Recarte V. , Gómez-Polo C. , Chernenko V.A.
Published: December 2018

The internal friction, the elastic modulus and the AC magnetic susceptibility of a near stoichiometric Ni2MnGa polycrystalline sample with low transition temperatures have been measured as a function of temperature by resonant ultrasound spectroscopy (RUS) and superconducting quantum interference device (SQUID) measurements. An internal friction peak and two minima in the elastic modulus have been observed, corresponding to the weakly first order transition from the cubic L2 _{1} parent phase to the intermediate phase (at T_{I} ≅ 213 K) and to the Martensitic Transformation (at T_{M} ≅ 100 K). The real part of the magnetic susceptibility shows a decrease and the imaginary part a peak at T_{I} .
Behavior-based control of robotic hand by tactile servoing
Authors: Park No-Hoon , Oh Yonghwan , Oh Sang-Rok
Published: December 2018

In this paper, we studied a behavior-based architecture to understand environment and perform manipulation through tactile servoing, especially by Chained Releaser Subsumption Architecture. This CRSA has the releasers which connect upper level with lower level. In order to verify the effectiveness of the CRSA, a 4 degree-of-freedom hand was designed and several behavioral grasping simulations and experiments are performed. In the simulations, the graphical behavioral performance was obtained as well as the trajectories of each of the fingers. In the experiments, some of the behaviors were initiated at level 1 to level 2. While the robotic hand performed grasping behaviors, the control program took the data from the DC motors and FSR sensors to make plan for future behaviors. The experiment results show that it is possible to control a robotic hand by behavior-based tactile servoing strategies.
Some results on the design of brushless DC wheel motor using SQP and GA
Authors: Moussouni F. , Brisset S. , Brochet P.
Published: December 2018

The sequential quadratic programming and genetic algorithms are finely tuned on the optimal design of a brushless DC wheel motor. Combining both methods, a hybrid approach is tested. Multiobjective optimizations are performed using Nondominated Sorting Genetic Algorithm, Strength Pareto Evolutionary Algorithm, and a variable weighted sum of objectives with the sequential quadratic programming. The Pareto fronts are compared in term of accuracy, uniformity, and coverage criteria using some quality indicators.
Dedicating Finite Volume Method to electromagnetic plasma modeling: Circuit breaker application
Authors: Rondot Loïc , Mazauric Vincent , Delannoy Yves , Meunier Gerard
Published: December 2018

A magnetodynamic formulation is developed using the Finite Volume Method to address specific issues in multiphysics involved in circuit breaker modeling. The principles of Finite Volume Method and multiphysics coupling method are described. The magnetostatic formulation is validated through two examples by comparison with two analytical solutions. Both problems are expressed within current based T _{0} − � formulation which differs drastically from other developments given in the context of Finite Volume Method. Finally a circuit breaker simulation is carried out within a magnetostatic formulation.
Optimization of a 3D micro-accelerometer based on diamagnetic levitation
Authors: Pigot Ch. , Delinchant B. , Poulin G. , Reyne G.
Published: December 2018

Scale reduction improves the amplitude of diamagnetism. Thus diamagnetic levitation is possible at the microscale with simple micromagnets. The present work aims at comparing the performances of this levitation at the microscale with other well established technologies. A device including a levitating magnet in a diamagnetic box is optimized in order to fulfil the requirements of three different markets in the acceleration sensing field. It is shown that this technology fulfils the requirements for medium range and short time response markets. However, the use of small proof mass limits the resolution of high precision sensors.
Natural convection in an enclosure under the influence of time-periodic magnetic field
Authors: Jalil Jalal M. , Al-Tae'y Kays A.
Published: December 2018

A two-dimensional thermal laminar natural convection of molten gallium in square enclosure isothermally heated and cooled from a side vertical wall was numerically computed in both time-periodic magnetic and gravity fields. The magnetic field is described by a sinusoidal time-varying equation. The thermal coefficient heat transfer has been calculated for various magnetic field strengths, but at a certain value of frequency and for different frequencies, but at a certain value of magnetic field strength. The results show that the effect of the time-periodic magnetic field on the flow field and heat transfer is lower than that of steady (DC) magnetic field effect at the same magnetic field strength.
Characteristic analysis of magnetic flux concentration type surface magnet motor
Authors: Eguchi Keisuke , Todaka Takashi , Enokizono Masato
Published: December 2018

This paper presents results of magnetic characteristic analysis of a magnetic flux concentration type surface magnet motor. Firstly influence of number of the rotor poles on the torque characteristics was examined for fixed stator construction and then some constructions of the permanent magnet array were tested to reduce the cogging torque. Their magnetic flux distributions and torque characteristics were calculated by using the finite element method.
Assessment of nuclear fuel pellets using X-ray tomography
Authors: Lekeaka-Takunju Peter , Khan Tariq , Bardel Charles , Udpa Satish , Udpa Lalita , Kim Jaejoon , Krzywosz Kenji
Published: December 2018

Fuel rods in nuclear power plants consist of uranium dioxide pellets enclosed in Zirconium alloy (Zircaloy) tubes. It is vitally important for the pellet surface to remain free from pits, cracks and chipping defects after it is loaded into the tubes to prevent local hot spots during reactor operation. The inspection of the fuel rod presents several challenges. In this paper, we investigate the feasibility of using X-ray tomography inspection to detect flaws on the surface of pellets contained within the tubes using very limited number of projections.
Research on influence of stator shapes and frames of switched reluctance motor to thermal characteristics
Authors: Li Jian , Song Xueguan , Choi Dawoon , Cho Yunhyun
Published: December 2018

This paper describes a comparison of thermal characteristics of stator shapes and frames in switched reluctance motor. It has been published that stator shapes and frame shapes had a large influence on noise and vibration performance, but thermal characteristics haven't been studied. Four different stator shapes were analyzed by using transient magnetic analysis in order to calculate the losses, which were taken into thermal analysis as heat source. Three dimensional finite element thermal analyses was then carried out to study four different stators with same basic dimension, and it was found that the square shape was most heat conductive. Frames including conventional axial ribbed aluminum frame, axial ribbed iron casting frame, radial ribbed frame, no ribbed frame were modeled and analyzed. The simulation results could be used to help make a choice between different stators and frames considering both vibration behavior and thermal behavior.