bluuebunny/crossref_metadata_2025 huggingface dataset:
Least square support vector machine network-based modeling for switched reluctance starter/generator
Authors: Ding Wen , Liang Deliang
Published: December 2018

This paper presents the least square support vector machine (LS-SVM) network as a new tool to develop the model of the switched reluctance machine(SRM) and predict the dynamic performances of SRM system. The basic premise of LS-SVM regression is that it forms a very efficient mapping structure for the nonlinear SRM. By using the measured sample data of SRM, the LS-SVM is designed to learn the nonliear magnetization data with rotor position and phase current as input, and the corresponding flux linkage and torque as output. It has a good capability of generalization and is computationally efficient. With the developed modeling method, a LS-SVM current-dependent inverse flux linkage model and a LS-SVM torque model are used to simulate the dynamic performances of a 6/4 SRM operating as a starter/generator, and the accuracy of the model is tested via comparison to the measurements of steady state phase current characteristics.
Optimization design of eddy current sensor for fuel balls detection based on electromagnetic field simulation
Authors: Zhang Liang , Han Zandong , Wang Bingfang
Published: December 2018

The fuel balls counter is used to monitor the ball-passing information in the transmission pipeline of high temperature gas-cooled reactor(HTGR). It's the eye of fuel handling system and plays an important role in ensure the reactor's safe work. Regarding the high temperature and radioactive environment in fuel handling system, eddy current testing method is the best choice for fuel balls detection. Because of the magnetic shielding of the thick walled stainless steel pipe, the ball-passing signal is weak. In order to increase signal to noise ratio and anti-interference ability, the parameter optimization of the sensor is performed by electromagnetic field simulation in this paper. The optimal goal is to maximize the coil impedance changing ratio between conditions of with and without ball inside pipeline.
Investigation of an on-line pipe wall defect monitoring sensor
Authors: Tagawa Akihiro , Fujiki Kazunari , Kojima Fumio
Published: December 2018

This paper presents development of a defect monitoring sensor using electromagnetic acoustic transducer (EMAT). The present study investigates the possibility of the defect monitoring using a new EMAT structure. The current EMAT was unsuitable for monitoring because of the large sensor area, and also it was necessary to have a mechanical scanning. Therefore, it was developed a new EMAT, smaller in size which does not need a mechanical scanning. The new EMAT was manufactured for a trial purpose. Based on the result of the performance test, it was found out that the new EMAT is able to monitor a defect and also to monitor both a thin and thick piping wall.
The numerical integration algorithm of dual bessel function and its application
Authors: Li Ming , He Wei , Li Qian , Xu Zheng , Luo Cong
Published: December 2018

A new numerical integral method of the Hankel transform which included the dual Bessel function in the integrand was presented. Because of the strong-oscillation and slow-decay properties of the Bessel functions, it is impossible to use a normal numerical integration method. In our method, the integral interval [0, ∞) is divided into two parts: [0, λ _0 ] and [λ _0 , ∞). In [0,λ _0 ], the integration can be calculated using a Gauss-Legendre quadrature method between the adjacent zero points. And in [λ _0 , ∞), the Hankel transform is converted to the Fourier cosine or sine transform, and can be calculated with a polygonal approximation algorithm. The proper value of the dividing point ofλ _0 was discussed. The simulation results of the test functions show that the algorithm is correct and accurate. Finally, the forward problem of the multi-layer medium magnetic induction tomography was calculated with this new method, and the eddy current distribution in the model and the induced voltages in the detection coils were simulated.
Estimation simulation of mri visualization using phase shift by nano-size ferromagnetic particles
Authors: Demachi Kazuyuki , Zhu Haitao , Mizutani Yurika
Published: December 2018

The phase shift component of MRI image was simulated for the tumors including the ferromagnetic particles by DDS which yielded the magnetic field distortion around the tumors. The simulation clearly visualized the shape and position of tumors. This method can image selectively only the tumors including the ferromagnetic particles by DDS, and so will be useful for the early finding of small tumor that are difflcult to be found by coventional techniques.
Modeling of Switching Ripple Currents (SRCs) for magnetic bearings including eddy current effects
Authors: Tian Yongsheng , Sun Yanhua , Yu Lie
Published: December 2018

In magnetic thrust bearings (MTBs), eddy currents induced in the solid stator and thrust disk not only result in performance degrading of the bearing, but also influence the SRC of the coil when driven by a switching power amplifier. In this paper, a fractional differential equation (FDE) model of the SRC considering the effects of eddy current is proposed and a numerical solution can be obtained from it by a predictor-corrector algorithm. Results from finite element method (FEM) and experiments show its validity. The presented model can be applied to the studies of self-sensing of non-laminated magnetic bearings.
The optimum design of the electric shield in writing probes for electric polarization data storage devices
Authors: Choi Jae-Hak , Chun Yon-Do , Han Pil-Wan , Koo Dae-Hyun , Im Jong-Bin , Lee Ju
Published: December 2018

This paper deals with the design of the structure and shape of writing probes in alternative electric data storage devices based on electric polarization fields. In order to design high recording density electric recording devices, the shape of the writing probe is optimized using a response surface methodology. The structure of a writing probe is also investigated according to the existence and nonexistence of the electric shield. The static and dynamic characteristic of recording density is analyzed and compared with conventional recording devices based on the magnetic magnetization field.
Active vibration control of plates using electro-magnetic constrained layer damping
Authors: Niu Hongpan , Zhang Yahong , Zhang Xinong , Xie Shilin
Published: December 2018

This paper investigates vibration control of plate through Electro-Magnetic Constrained Layer Damping (EMCLD) which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. The equivalent current assumption is adopted to model the magnetic control force produced by EMCLD. The governing equations of the plate system are obtained using Hamilton's Principle. A simulation and an experiment on vibration control of a cantilever plate are done under the velocity proportional feedback to demonstrate the active control capability of EMCLD. Both the results of simulation and experiment show EMCLD is an effective means for active vibration control.
Position control of a dual-stage actuator
Authors: Sasaki Minoru , Ozeki Tomohito , Ito Satoshi , Tamagawa Hirohisa
Published: December 2018

This paper describes the position control of a dual-stage actuator with piezoelectric actuator using self-sensing actuation. The dual-stage servo system consists of a coarse actuator and a fine actuator. A DC servo motor is used as the coarse actuator, and a piezoelectric actuator provides fine control. The position control of the dual-stage actuator using the dual feedback method and self-sensing is presented. Experimental results show the validity of the proposed control system
A magnetoelastic model of nonlinear behaviors of Tb-Dy-Fe alloys based on domain rotation
Authors: Pei Yongmao , Fang Daining
Published: December 2018

A magnetoelastic constitutive theory of nonlinear anhysteretic behaviors based on domain rotation is presented in this paper for giant magnetostrictive materials (GMMs). For a Tb-Dy-Fe polycrystal with preferred orientations, the magnetic moments of domains are constrained by the anisotropy to lie along the <111> easy magnetization directions. Thus, the fractional occupancies of only the eight<111> directions and the field direction are calculated using an inverse exponential distribution function for simplicity. The linear fitting of the potential distribution parameter with the pre-stress is obtained from the magnetization curves under different compressive stresses for a [110] oriented Tb-Dy-Fe rod, which is used to predict the magnetostriction behaviors. It shows good quantitative agreement with the experimental results under a range of constant uniaxial compressive stresses.
Robust oriented particle swarm optimization algorithm applied to inverse problems
Authors: Yang Shiyou , Wu Lie , Yang Lin , Xiong Suming
Published: December 2018

This paper proposes a particle swarm optimization algorithm to find the robust solution of an inverse problem in which uncertainties or perturbations are inevitable. To reduce the heavy computational burden for expected fitness evaluations, a strategy to assign expected fitness only to the best solution searched by a particle in every iterative cycle is proposed, a repository is introduced to memory the searched history and then employed to determine the expected fitness value of a specific solution. The simplex method is used to find the worst case solution of a potential candidate to consider hard constraint functions. The numerical results serve to demonstrate the pros and cons of the proposed algorithm and the necessity to devote efforts in the development of robust oriented optimal algorithms.
A new effective method for removing measurement noise in eddy current nondestructive inspection
Authors: Sun Xiao-Yun , Liu Dong-Hui , Sheng Jian-Ni
Published: December 2018

For tube detection, an effective denoise method based on Hilbert-Huang Transform (HHT) is presented. At first, by using an empirical mode decomposition algorithm, a sum of Intrinsic Mode Functions (IMF) are obtained; then, the IMF coefficients in useful signal dominative layer are proceeded using soft threshold method; at last, those IMF coefficients are reconstructed. Compared with the traditional wavelet Transform, the HHT method is better to remove measurement noise.
Calculation on the magnetic field around the distribution substation and analysis on the shielding measures
Authors: Yang Fan , Kang Lihong , He Wei , Duan Huiqing
Published: December 2018

The magnetic field (MF) produced by the bus bars in the urban distribution substation can pollute the environment, and shielding measures should be taken. In the paper the model to calculate the power frequency magnetic field around an urban distribution substation is presented firstly, then the calculation on the magnetic field produced by the three-phase bus bars was carried out, and influence on the magnetic field distribution caused by different parameter was analyzed. The results indicate that to decrease the magnetic field in the upper floor, it's better to make the distance between the bus bars within 0.4 m, and the height of the bus bars within 0.1 m. Then the shielding measures to eliminate the magnetic field in the upper floor residential housing were investigated, and results indicate that the smaller size of the reinforced grid and the greater diameter of the reinforced bar, the better is the shielding effectiveness. For the shielding of the magnetic field in the up floors, the shielding effectiveness can reach 33.52 dB with an 8 mm thick shielding steel plate used in the floorboard. Considering the economic cost, the shielding grid made of 8# reinforced bars (net size: 0.10*0.10 m ^{2} , the diameter of the reinforced bar is 8 mm) is the best for the MF shielding.
Evaluation of geometrical shape in fatigue cracking using ECT signals
Authors: Oshima Kenichi , Kojima Fumio
Published: December 2018

Our study is aimed at developing a practical method for identifying the cracking geometrical shape from surface image obtained by scanning eddy current testing (ECT) probe. A various type of fatigue cracks are made from compact tension (CT) specimen of aluminum alloy samples. ECT signals are collected for those test samples using the absolute pancake probe. We discuss the features of ECT detecting signals of fatigue cracking which are different from electric discharge machining (EDM) crack signals.
Quantitative nondestructive estimation of deep defects in conductive structures
Authors: Li Guohou , Huang Pingjie , Chen Peihua , Hou Dibo , Zhang Guangxin , Zhou Zekui
Published: December 2018

Eddy current testing (ECT) is a widely used nondestructive testing method in many such fields as the power system, railway, machinery, aircraft and nuclear industries. Because of the limitation of penetration depth of the conventional eddy currents testing coils and other affecting factors existing in the eddy current response, inverse problems to evaluate the deep defects from ECT signals of the conductive materials have been a challenging task. The objectives of this study are to introduce methods based on the fuzzy Bayesian networks (BNs), and the giant magnetoresistance (GMR) sensors to estimate the deep defects from their ECT signals. The experimental validation carried out on the specimens with different known defects confirmed the suitability of the proposed approach for deep defects evaluation.
The research on the flaw classification and identification of the PEC NDT technology
Authors: Wang Haitao , Zhang Binqiang , Tian G.Y. , Zhou Deqiang , Wang Ping , Li Yong
Published: December 2018

Pulsed Eddy Current (PEC) NDT has played a vital role in detection and classification of the surface and sub-surface defects in conductive structures. Normally, it uses peak values of the acquired transient field signals, and the combination of the feature values of the time of the peak to identify flaws with the help of Principal Component Analysis (PCA). However, it is found that the random noise undermines the classification results, because PCA works robustly only in the time domain. In the light of this drawback, the fundamental and the first-harmonic components are investigated and taken as the new feature values in the frequency domain. Through the analysis of the feature values in both time and frequency domains, the influence of random noise is mitigated. Consequently, surface defects, subsurface defects and metal thickness changes are classified with much higher identification accuracy.
Control strategies for an improved single power hybrid asymmetrical multilevel converter
Authors: An Qun-Tao , Sun Li , Sun Xing-Tao , Zhao Ke
Published: December 2018

A novel single power hybrid asymmetrical multilevel converter(SPHAMC) topology is proposed. By adding an assistant leg to control the neutral-point voltage independently, the presented converter conquers the difficulties of controlling the neutral-point voltage and the sub-converter capacitor voltages in traditional SPHAMCs. The related control strategies are studied in this paper. In order to ensure the stability of the sub-converter capacitor voltages, a PI regulator is employed to control the main converter output voltage. Redundant states selection (RSS) and duty cycle modulation(DCM) methods are implemented to regulate the sub-converter capacitor voltages during each output voltage period. The simulation results as well as experimental ones illustrate the validity and efficiency of the proposed topology and control strategies.
Novel remedial control strategies for fault-tolerant pwm inverters
Authors: An Qun-Tao , Sun Li , Zhao Ke , Sun Li-Zhi
Published: December 2018

The reliability of PWM inverters is direct related to the safety of motor drive systems. Three-phase four-switch inverter (TPFSI) as a fault-tolerant topology is studied and space vector pulse width modulation(SVPWM) for TPFSI is investigated in this paper. The essence of four-switch SVPWM (FS-SVPWM) is revealed. In order to improve the utilization rate of the DC link voltage, a compensatory voltage vector based over-modulation method for FS-SVPWM is proposed. The simulation and experimental results validate the proposed algorithm.
Non-contact control of elastic vibration with magnetic damping for non-ferromagnetic plate
Authors: Niho Tomoya , Horie Tomoyoshi
Published: December 2018

This paper describes a method for non-contact vibration control of non-ferromagnetic conductive structures using electromagnetic force. This method has potential applications in conventional engineering and medical engineering. Elastic vibration is induced by an electromagnetic force, which is produced by the interaction between a magnetic field and the eddy currents induced by a transient magnetic field. Since the intensity of the electromagnetic force changes with the intensity or time variation of the transient magnetic field, the amplitude or time variation of the elastic vibration can be controlled by the transient magnetic field. On the other hand, the electromotive force induced by the deformation velocity and magnetic field reduces the vibration, which is referred to as the magnetic damping effect. Since the magnetic damping effect reduces vibration and induces a time delay in the vibration response, consideration of the magnetic damping effect is required for non-contact vibration control of non-ferromagnetic structures using electromagnetic force.

In this study, a method for controlling the vibration of non-ferromagnetic conductive structures using electromagnetic force is proposed, which is based on theoretical and one-degree-of-freedom models of vibration with magnetic damping. The parameters of the model are determined on the basis of the coupled eigenvalues obtained from the coupled finite element equation. Feedback control is also used to realize vibration control. In order to examine the validity and performance of the proposed vibration control method, vibration control experiments are carried out for various desired amplitudes and frequencies of vibration.
A magneto-elastic sensor for screening of body position and mobility during sleep
Authors: Traxler Stefan , Pfútzner Helmut , Mijanović Lejla , Popović Jovana , Kaniusas Eugenijus , Futschik Karl
Published: December 2018

The paper concerns a detector for biomedical screening of sleep apnea which may yield severe reduction of life expectation. The detector is mounted on the thorax including several sensors for respiratory and cardiac activities. An additional magneto-elastic sensor, which is described in this paper, should register both the body position and body movements, both being relevant for diagnostics.

The sensor is based on a magneto-elastic bilayer of high bending sensitivity operated in acceleration mode. The sensor is being optimized with respect to material matching, loading (mass optimization) and length, as well as (limited) excursion, resonance frequency and thermal behavior.

Application is reported for lab tests on short time events of three kinds: (a) body positions, with focus on back position which favors positive findings, (b) body movements, ranging from arm/leg movements up to upper body rolls, and (c) physiological activities such as respiration, indicating additional potentials of the sensor.

The magnetic concept promises a component which is compact, robust, free of wear and cheap. It will be used in combination with sensors for respiration effort and cardiac activity, aiming for a robust single-spot home monitoring device for the assessment of sleep apnea syndrome.
Tracking position control of a linear actuator on distributed control network
Authors: Song Ki Won , Choi Gi Sang , Choi Gi Heung
Published: December 2018

Tracking position control of a linear magnetic actuator implemented on distributed control network was studied. In the distributed control system involving a discrete-time controller and a linear magnetic actuator, time delay happens as the controller reads the sensor data or sends out the control input to the actuator located at a local or a remote site. In many cases the time delay is not ignorable, and has significant effect on the control system performance. In order to compensate for the adverse effect of the time delay, the modified Smith predictor was introduced to the control system. The results of simulation and experiment show that the performance of linear magnetic actuator can be improved by augmenting the modified Smith predictor onto the existing control system. With the modified Smith predictor, the position error is reduced and the constant disturbance is suppressed.
A comparison of two formulations for magnetic field synthesis on a cylindrical solenoid's axis
Authors: Ziolkowski Marcin , Gratkowski Stanislaw , Yatchev Ivan
Published: December 2018

In various engineering and biomedical disciplines often there is a need to design an electromagnetic arrangement which is able to generate a magnetic field of demanded distribution. Such a problem also takes place in magnetic field active shielding designing. In this case solenoids that generate an opposite magnetic field to the external field in the region of interest are used. This paper discusses the problem of finding the shape of a solenoid which produces a given magnetic field magnitude on the axis. Two different methods are used and compared: iteratively regularized Gauss-Newton method and genetic algorithm based method with the use of Bezier curves.
Optimization of a power mosfet and its monolithically integrated self-powering circuits
Authors: Nguyen-Xuan H. , Gerbaud L. , Rouger N. , Crébier J.-C. , Yatchev Ivan
Published: December 2018

The paper presents a physical structure optimization of an integrated semiconductor device: a power MOSFET and other vertical transistors are integrated within the same die, introducing a novel self supplied power transistor. This integrated optimal design leads to complex optimization problems with close constraints. The main constraint model deals with the avalanche phenomenon that is formulated by multiple integral expressions of implicit functions. The paper focuses on two aspects: the integral formulation of the avalanche model and more specifically its gradient computation in the aim of applying a gradient-based optimization algorithm, and the comparisons of several optimization methods on this problem.
A real-time tracking method for the rectangular magnet based on parallel Levenberg-Marquardt algorithm
Authors: Yang Wan'an , Li Yan , Hu Chao , Song Shuang
Published: December 2018

magnetic flux intensity of the rectangular magnet is the function of its location and orientation. With the measured magnetic flux intensities at two points around the rectangular magnet by 3-axis magnetic sensors, a non-linear equation group is established, and the location and orientation of the rectangular magnet can be determined by seeking the solution of the equation group by using general Levenberg-Marquardt (L-M) algorithm. However, the time occupied by general L-M algorithm is too long to realize real-time tracking for the rectangular magnet. We propose an improved method which computes Jacobin Matrix in L-M algorithm in parallel. Making use of the Open Multi-Processing (OpenMP) model, the parallel operation is implemented on the dual-core personal computer. As a result, the real-time tracking for the rectangular magnet is realized, and the tracking curve is smooth.
Triple Langmuir probe diagnosis of transient plasma created by hypervelocity impact
Authors: Tang Enling , Zhang Qingming , Xiang Shenghai , Yang Minghai
Published: December 2018

To acquire the characteristic parameters of plasma generated by hypervelocity impact, experimental system and a new Triple Langmuir probe diagnostic system are established in the paper. Triple Langmuir probe diagnostic technology does not require a voltage or frequency sweep compared to other Langmuir probe methods. The system allows the direct display of electron temperature and semidirect display of electron density by appropriate display system, this method eliminates the time consuming in data analysis required in curve-fitting current-voltage characteristics. As an example of application to time-dependent plasmas measurement, the electron temperature and electron density of plasmas were measured in hypervelocity impact experiments. Experimental results show that the Triple Langmuir probe diagnostic technology can be well used to measure electron temperature and electron density of time-evolution plasma.
Effect of background magnetic field on the electron-bunching and saturation phenomenon in a gyro-TWT
Authors: Singh R.K.
Published: December 2018

A self-consistent nonlinear simulation model has been presented to analyze the nonlinear behaviour of a gyro-TWT amplifier. It employs a slow-time scale formulation such that the numerical calculation time and the number of numerical integration steps have been drastically reduced. Beam-wave interaction mechanism has been presented with the help of electron flight diagram. The effect of variation of the static magnetic field on the bunching of the electrons along axial direction has also been clearly presented. The electron flight diagram thus obtained clearly demonstrates the electron defocusing and its effect on the saturation behaviour of the device.
Applying FEM-RBCI to the analysis of plasmons in metallic nanoparticles
Authors: Aiello Giovanni , Alfonzetti Salvatore , Brancaforte Valentina , Chiarello Viviana , Salerno Nunzio
Published: December 2018

In this paper the FEM-RBCI method is successfully applied to the analysis of the scattering of time-harmonic electromagnetic waves at optical frequencies from metallic nanoparticles. Plasmons are taken into account by modelling the nanoparticles by means of appropriate complex permittivities. The method is valid whatever the shape of the nanoparticles. Numerical examples are provided to validate the method.
Assessment of ion cyclotron antenna performance in ASDEX Upgrade using TOPICA
Authors: Ceccuzzi S. , Braun F. , Bobkov V. , Cesario R. , Krivska A. , Maggiora R. , Milanesio D. , Mirizzi F. , Noterdaeme J.-M. , Ravera G. , Tuccillo A.A. , Zammuto I. , ASDEX Upgrade team The
Published: December 2018

Nuclear fusion in magnetic confinement devices is one of the most challenging application fields for electromagnetics and mechanics. In particular antennas, charged with the task of handling and delivering high power to the plasma, have to operate in a harsh environment with very demanding thermal and mechanical requirements. Within this scenario, the use of tools able to efficiently predict the antenna behaviour is mandatory. In the present work, the TOrino Polytechnic Ion Cyclotron Antenna (TOPICA) code has been used to simulate the real 3D geometry of two launchers, generally operating at 30 MHz and presently installed on the ASDEX Upgrade tokamak. The working frequency belongs to the Ion-Cyclotron range of frequencies that was proven to achieve very efficient plasma heating. Antenna performances are presented in terms of coupled power and RF potentials for different realistic plasma scenarios taken from ASDEX Upgrade.
Identification of wire breakage status based on the measurement and inversion of magnetic field aiming at applications to cable in conduit conductors of ITER magnets
Authors: Tian Shuxia , Chen Zhenmao , Li Yong , Zuo Yongbin , Wang Xiaowei
Published: December 2018

The wire breakage identification of superconducting multistrands Cable in Conduit Conductors (CICC) is a key point to guarantee the reliability of the magnet system of the International Thermonuclear Experimental Reactor(ITER). In this paper, a Nondestructive Testing (NDT) method based on the measurement of magnetic fields surrounding CICC and the reconstruction of the current values in the superconducting cables from the measured magnetic field signals is presented. The validity and efficiency of the proposed method are demonstrated through numbers of numerical simulations and preliminary experiments.
A new version of coaxial holder with continuous conductor for tests on planar films
Authors: Desideri Daniele , Maschio Alvise
Published: December 2018

A new version of coaxial transmission line sample holder with continuous conductor for measurement of shielding effectiveness of planar films has been developed. The inner conductor of the sample holder is divided in two parts; at one end of the two parts an internal and an external straight thread respectively have been realized. The connection of the inner conductor is done by screwing the two parts, pressing the film and its substrate between two flat annular surfaces. The contact is simple, reliable and effective. Contact resistance value of the order of milliohm has been obtained with a copper film deposited on PEEK substrate. With the deposited copper film, shielding effectiveness measurements in the frequency range 10 kHz–300 MHz have been done and are reported.
Defect detection in transition zones of sucker rods using magnetostrictive guided waves
Authors: Xu Jiang , Wu Xinjun , Kang Yihua
Published: December 2018

The guided wave technology is usually applied to detect defects in the regular zone. In this paper, the guided wave technology is applied to detect the flaw in the transition zone of sucker rods where is an irregular zone. A piecewise model is established by making a difference between the down step flaw and the up step flaw. The experiments are carried on a sucker rod sample with the artificial notch flaws in the transition zone using magnetostrictive guided waves. The experimental results agree well with the theoretical predictions. The result indicates that the guided wave technology could be applied to inspect some special irregular structures.
Evaluation of inductance coil and fluxgate magnetometer under harmonic and pulsed excitations in ECT
Authors: Smetana Milan , Janousek Ladislav
Published: December 2018

The article deals with utilization of two various types of sensing elements in eddy current non-destructive testing. An inductance coil and a fluxgate magnetometer are employed to pick-up the response signals from artificial slits. The sensitivity and the resolution of the two types of sensors are analysed under the same conditions. The sensors' performances are compared under the harmonic excitation and the pulsed one as well. Numerical simulations and experimental measurements are carried out for performing the evaluation. The gained results are presented and discussed in the paper.
Decline in ambiguity of partially conductive cracks' depth evaluation from eddy current testing signals
Authors: Janousek Ladislav , Smetana Milan , Alman Marcel
Published: December 2018

The paper deals with eddy current non-destructive inspection of partially conductive cracks. A non-magnetic conductive plate specimen is examined using numerical simulations. A crack with the rectangular shape is modelled in the middle of plate. Dimensional parameters and the conductivity of the crack are varied in wide ranges to imitate diversity of practical scenarios. A new eddy current probe is designed for the near-side inspection of the plate. An exciting system of the probe drives uniform eddy currents in the plate and all the three spatial components of the perturbation electromagnetic field are sensed with a magnetic sensor. Influences of the crack's partial conductivity as well as its dimensions on the perturbation field's components are studied in order to enhance evaluation of real partially conductive cracks.
Multi-frequency Eddy Current Testing using a GMR based instrument
Authors: Bernieri Andrea , Betta Giovanni , Ferrigno Luigi , Laracca Marco
Published: December 2018

The paper proposes the use of a suitable multi-frequency approach applied to a novel instrument for eddy current non-destructive testing on conductive materials. The instrument is composed by a smart eddy current probe, based on a Giant Magneto Resistance sensor, and by a suitable processing unit. Key features of the proposed instrument are the capability of detecting, locating, and characterizing thin defects such as superficial and sub-superficial cracks. The proposed multi-frequency solution, together with a suitable data processing, allow both the sensitivity in the defect detection to be increased and the ability to evaluate the defect characteristics in terms of shape and dimension to be improved.
Numerical simulation of phased-array laser ultrasound and its application for defect inspection
Authors: Pei Cuixiang , Demachi Kazuyuki , Zhu Haitao , Koyama Kazuyoshi , Uesaka Mitsuru
Published: December 2018

In this paper, a numerical code is developed for the analysis of phased-array laser ultrasound. The signal enhancement of ultrasonic waves induced by a multi-beam laser source in phased array is simulated by using finite element method (FEM). The use of phased-array laser ultrasound for crack inspection with shadow method is investigated by simulation method.
Modelling of the blood flow and pressure waves reflections in vessels
Authors: Čáp Ivo , Čápová Klára , Gombárska Daniela , Czippelová Barbora
Published: December 2018

Modelling of blood flow in vessels offers a useful tool for vascular system examination. Propagation of blood pressure and blood flow pulses are analyzed in the present paper. The pulses shapes are significantly influenced by their reflections at vessels inhomogeneities. The whole body arterial model is used for different phenomena investigation. Influence of waves' reflections on their profiles is examined. Consequences of vessels bifurcations, stenosis and sclerosis are simulated and the simulated results are compared with experimental data taken by means of PPG.
Preliminary study of a magnetically driven muscle-like actuator
Authors: Ma Quanchao , Wang Ming , Zhao Chunxia , Luo Yun
Published: December 2018

This paper proposes a muscle-like actuator inspired by the agonist-antagonist characteristic of biological muscles. As a preliminary study, we designed an agonist-antagonist actuator with a magnet pair as an agonist, elastic components as an antagonist, and an electromagnetic trigger. The mechanical properties of the magnet pair and the trigger were analyzed using the finite element method. In the experiments to verify the feasibility of the actuator, two types of elastic components (rubber bands and polymer tubes with a specific structure) were respectively utilized. The effectiveness of the actuator was confirmed by experiments.
Electromagnetic design for performance improvement of an MR valve
Authors: Lee Hyung-Don , Nam Yun-Joo , Park Myeong-Kwan
Published: December 2018

This paper is concerned with an electromagnetic design methodology for a magneto-rheological (MR) valve. In order to improve the performance of the MR valve, the magnetic circuit consisting of the MR fluid, the yoke for forming the magnetic flux path, and the electromagnetic coil should be effectively designed. For this purpose, two effective approaches are proposed: one is to shorten the magnetic flux path by removing the unnecessary bulk of the yoke to improve the static characteristic of the MR valve, and the other is to increase the magnetic reluctance of the magnetic circuit by minimizing the cross-sectional area of the yoke through which the magnetic flux passes to improve the dynamic and hysteretic characteristics. After two MR valves, one is a conventional type valve and the other is the proposed one, are designed and fabricated, their performances are evaluated through magnetic field analysis and a series of basic experiments.
Experimental investigation on heat transfer characteristics in rectangular duct flow of a magnetic fluid under magnetic field
Authors: Motozawa Masaaki , Chang Jia , Sawada Tatsuo , Kawaguchi Yasuo
Published: December 2018

Forced convective heat transfer characteristics in a rectangular duct flow of a magnetic fluid under a magnetic field were investigated experimentally. Experiments were performed in which the magnetic field intensity was changed from 0 mT to 500 mT. The Reynolds number based on the hydraulic diameter was set to 820 (laminar flow), 1630 and 2450 (turbulent flow). The magnetic fluid in the rectangular duct was heated with a uniform heat flux. The results of the experiments showed that in the case of laminar flow of the magnetic fluid, when the magnetic field is applied to the magnetic fluid flow, the heat transfer coefficient increases locally in the region where the magnetic field exists. In contrast, in the turbulent flow of the magnetic fluid, heat transfer is not enhanced, but slightly decreases.
Smart magneto-elastic materials for passive damping applications
Authors: Davino Daniele , Giustiniani Alessandro , Visone Ciro
Published: December 2018

The analysis of a passive damper employing smart materials is carried out through the description of a concept device loaded by a vibrating mass. Such a device is able to damp vibration and to produce electric energy (energy harvesting). Its basic properties are described in detail and the relationships between damping features and its physical parameters are shown. The analysis is carried out by a linear modeling at first, while the comparison to its actual behaviour is exploited to justify a more careful study where the material non-linearity is considered. Analytical results on the linear model and the spice numerical analysis of a non-linear model are presented.
Field synthesis in a magnetic subdomain with arbitrarily discretized boundary
Authors: Di Barba Paolo , Savini Antonio
Published: December 2018

An approach based on the use of Thévenin-like conditions, in order to define a reduced domain for finite-element analysis (FEA), is proposed to help the solution of optimal synthesis problems in a cost-effective way. In particular, the mismatch of nodes discretizing the common boundary between reduced and complementary domain is considered. A case study in 2D magnetostatics, where the field domain is an open-boundary region, is considered.
A comparative study of sensorless speed control
Authors: Lu An , Hameyer Kay
Published: December 2018

In this paper, a sensorless control scheme using back-EMF observer for permanent magnet synchronous motor drive (PMSM) is presented. Based on a general relationship between back-EMF and rotor position, observed rotor position is calculated and corrected with position estimation error. To obtain the velocity information from the observed rotor position, the velocity observer method and state of the art direct difference method are implemented and compared with each other.
Analysis and design of slotless tubular linear actuator for high performance on the eco-pedal system of vehicles
Authors: Kim Young-Kyoun , Gu Bon-Gwan , Rhyu Se-Hyun , Jung In-Soung
Published: December 2018

This paper presents the design and analysis of a slotless tubular linear actuator for the ecopedal system of a vehicle. To achieve high fuel efficiency in a vehicle, the electric actuator produces a counter force to the vehicle's pedal when pressed. The actuator requires a high level of performance, such as a high force density and low detent force. In this study, the design of the slotless tubular linear actuator was optimized to satisfy these requirements. The finite element method was used to analyze the actuator's electromagnetic properties, and the viability of the design result was verified experimentally.
Characteristic analysis of a hybrid excited flux switching PM motor by using the equivalent magnetic circuit method
Authors: Jang Jin-Soek , Lee Jae-Kwang , Kim Byung-Taek
Published: December 2018

This paper suggests a hybrid exited Flux Switching Permanent Magnet(FSPM) motor which has flux control characteristics. First of all, the structure of FSPM with flux control characteristics is suggested and the basic principle of how it works is explained. Then, a 2D model considering an overhang is suggested in order to extract the parameters of the motor and using this, counter back-emf and inductance are calculated. Lastly, the characteristics were analyzed using voltage equation when operating flux control.
Frequency response characteristics for linear actuator made by NiMnGa shape memory alloy
Authors: Oonishi Atsurou , Hirata Katsuhiro , Yoo Byungjin , Niguchi Noboru
Published: December 2018

This paper deals with the frequency response characteristics of a magnetically controlled shape memory alloy (MSMA) linear actuator made by NiMnGa alloy under external magnetic field. In order to predict the strain actuation of the linear actuator induced by external magnetic field at variable drive frequency, a new computational analysis method using finite element method (FEM) was proposed. The frequency response characteristics of the prototype linear actuator exhibited good agreement with the result of the proposed analysis method.
Minimization of cogging torque in permanent magnet machines using the topological gradient and adjoint sensitivity in multi-objective design
Authors: Putek Piotr , Slodička Marian , Paplicki Piotr , Pałka Ryszard
Published: December 2018

The paper presents an application of the topological derivative and continuum sensitivity analysis for the optimal design of the permanent magnet excited machines with the adjustable excitation. In our work we applied a topological optimization in order to find a general shape of rotor poles consisted of an iron and magnet part. An essential advantage of the proposed method is its numerical effectiveness. In order to verify results, three-dimensional models were developed and thoroughly analyzed. As presented in the comparative analysis of 3D results, the applied method lead to the significant reduction of both, the cogging torque and a level of higher harmonics in the voltage induced in the armature windings.
Optimal design of novel concentrated flux IPM type brushless DC motor
Authors: Lee Jin-hee , Lipo Thomas Anthony , Kwon Byung-il
Published: December 2018

This paper proposes a novel concentrated flux interior permanent magnet (IPM) type brushless DC (BLDC) motor that replaces low-price ferrite magnets, which has similar characteristics as the conventional IPM type BLDC motor that uses expensive NdFeB magnets. To minimize the cogging torque which is a disadvantage of the proposed model, optimal designs of rotor and permanent magnet were performed. In optimal design process, the Kriging method based on the Latin hypercube sampling (LHS) and a genetic algorithm (GA) are applied due to suitability to non-linear data. Furthermore, to improve the average torque of the proposed model, the current excitation range was changed according to inductance. Through the optimal design process and the proper current excitation range, we show that the optimal model using low-price ferrite magnets has similar performance as the conventional IPM type BLDC motor using NdFeB magnets.
Permanent magnet linear synchronous motor characteristics comparison with different topology structures
Authors: Zheng Zhan-Feng , Zhu Yu-Wu , Cho Yun-Hyun , Dong En-Yuan , Zou Ji-Yan
Published: December 2018

To make the ropeless elevator system (RLES) become practical, one of the most important requirements is the high force density. The slotted iron core type permanent magnet linear synchronous motor (PMLSM) seems to be the best choice except the large detent force. Therefore, in this paper the characteristics of detent force and propulsion force of PMLSM are investigated under different motor topology structures, such as different PMLSM topologies, different mover topologies, and different armature core topologies. Finally, the long stator double-sided slotted iron-core type PMLSM with fractional slot winding is selected for the best performance.
Wireless energy transmission device with thrust for transportation
Authors: Fujii Nobuo , Kanamitsu Shuhei , Mizuma Takeshi
Published: December 2018

The characteristics in the linear induction motor (LIM) mode of new wireless energy transmission device are cleared analytically. The apparatus operates as two types of LIM with propulsion force or a linear transformer without thrust. One type of the LIM is a secondary current controlled wound type of LIM with primary winding on ground and the other is the LIM with reaction plate on ground. The paper shows the characteristics of the wound type of LIM in power running and has the onboard power transmission function even in the power running. The two-dimensional finite element method (FEM) is used for the analysis. As a result, it is cleared that the model designed for urban transit has high efficiency and high input power factor respectively more than 0.9 for the optimal control.
Slip detection with multi-axis force/torque sensor in universal robot hand
Authors: Kobayashi Futoshi , Kojima Fumio , Nakamoto Hiroyuki , Kida Yasuaki , Imamura Nobuaki , Shirasawa Hidenori
Published: December 2018

A humanoid robot hand receives much attention in various fields. We have developed the universal robot hand with the multi-axis force/torque sensors. In order to manipulate an object by the robot hand without dropping the object, it is important to detect a slip between the object and the robot finger. Therefore, we propose a slip detection method with the multi-axis force/torque sensor and an anti-slip control method based on the slip detection. The effectiveness of the proposed slip detection and the anti-slip control is verified through some experiments with the universal robot hand.
Effective microwave magnetic response of two-component metaferrite
Authors: Rybin Oleg
Published: December 2018

The complex effective relative permeability of a two-component ferrite-like metamaterial was studied for the two cases of electromagnetic wave propagation with respect to direction of dc magnetic bias field, namely, parallel and transverse. The metamaterial of interest is the host dielectric with periodically embedded ferric cylindrical or spherical inclusions. The inclusions are saturated with the biasing magnetic field and the magnetic losses are taken into account. The analysis was performed utilizing the Microwave Effective Medium Theory for two-component artificial composite materials with saturated lossless ferric inclusions [1]. Computations revealed that low values of refractive index as well as negative values of permeability can be achieved.
Martensitic and magnetic domain structures in polycrystalline shape memory alloys Ni_{2+x}Mn_{1-x}Ga
Authors: Grechishkin R.M. , Koledov V.V. , Shavrov V.G. , Dikshtein I.E. , Khovailo V.V. , Takagi T. , Buchelnikov V.D. , Taskaev S.V.
Published: December 2018

The martensitic twin and magnetic domain structures of polycrystalline samples of the shape memory Ni _{2+x} Mn _{1-x} Ga alloys are studied by magnetooptic and Bitter colloid techniques. It is shown, that the analysis of the magnetic domain structure allows one to determine the martensitic structure characteristics, such as symmetry of phases and tetragonal axes orientation. A theoretical model is in good agreement with the experiment.
Reply to “Comments on “Transient electromagnetic field of dipole source in chiral medium” ” by A. Lakhtakia
Authors: Cheng Dajun
Published: December 2018

I acknowledge this comment [A. Lakhtakia, Int. J. Appl. Electromagn. Mech. 9(1) (1998), 89] and add that the original results [D. Cheng, Int. J. Appl. Electromagn. Mech. 8(2) (1997), 179], which treat the purely instantaneous response, are only useful for a chiral medium when it can be approximately considered to be nondispersive under certain specified conditions.