bluuebunny/crossref_metadata_2025 huggingface dataset:
2D Green's functions for two-phase orthotropic electro-magneto-thermo-elastic materials
Authors: Xiong Su-Ming , Hou Peng-Fei , Yang Shi-You
Published: December 2018

We use the 2D general solutions of orthotropic electro-magneto-thermo-elastic material to construct the 2D Green's function for a steady line heat source in the interior of two-phase orthotropic electro-magneto-thermo-elastic plane by ten newly introduced harmonic functions with undetermined constants. The corresponding coupled field can be obtained by substituting these functions into the general solution, and the undetermined constants can be obtained by the continuous conditions and equilibrium conditions. All components of coupled field are expressed in terms of elementary functions and are convenient to use.
Residual strain effects on a non-contact magnetoelastic torque transducer
Authors: Andreescu R. , Spellman B. , Furlani E.P.
Published: December 2018

A non-contact magnetoelastic torque transducer consisting of a non-magnetic shaft with a portion of its length coated with a magnetostrictive material is studied. A phenomenological theory is developed for predicting the magnetic field of the transducer as a function of coating properties, residual strain, and applied torque. This theory takes into account stress-induced anisotropy and variations in magnetoelastic energy within the coating. The resulting model is used to investigate the effect of quiescent stress states on the sensitivity, hysteresis and linearity.
Multiobjective design optimization and Pareto front analysis of a radial eddy current coupler
Authors: Canova Aldo , Freschi Fabio
Published: December 2018

The paper proposes a multiobjective optimization to design a radial eddy current coupler, where the torque is maximized while the momentum of inertia is minimized to improve the dynamic behavior of the device. An analytical solution of the electromagnetic problem is used to speed up the computation of objectives and an optimization algorithm based on the emulation of the immune system behavior, referred to as Vector Immune System, is adopted to find tradeoff solutions between objectives. The solutions found so far are compared with solutions obtained by a Genetic Algorithm with fuzzy scalarization of objectives. It shows a faster convergence with a better spread of trade-off solutions available for a higher level decision making. A deep analysis of these Pareto optimal configurations is also provided, trying to discover common properties of optimal solutions.
Image reconstruction of inhomogeneous biaxial dielectric cylinders buried in a slab medium
Authors: Sun Chi Hsien , Chiu Chien-Ching , Lin Chun Jen
Published: December 2018

The image reconstruction of inhomogeneous biaxial dielectric cylinders buried in a slab medium is investigated. A biaxial dielectric cylinder of unknown permittivities buried in a slab scatters a group of unrelated incident waves from outside. The scattered field is recorded outside the slab. By proper arrangement of the various unrelated incident fields, the difficulties of ill-posedness and nonlinearity are circumvented, and the permittivity distribution can be reconstructed through simple matrix operations. The algorithm is based on the moment method and the unrelated illumination method. Numerical results are given to demonstrate the capability of the inverse algorithm. Good reconstructed results are obtained even in the presence of additive Gaussian random noise in measured data. In addition, the effect of noise on the reconstruction result is also investigated.
Transparency improvement of a 1 DOF hybrid haptic device with wide-ranged torque reflection
Authors: Lee Do-Young , Nam Yun-Joo , Park Myeong-Kwan , Yamane Ryuichiro
Published: December 2018

This paper is concerned with the transparency improvement of a 1-DOF(degree-of-freedom) hybrid haptic device with the wide-ranged haptic reflection. The hybrid haptic device is actuated by the combination of an active actuator and a passive one. A noble hybrid concept for the haptic device is proposed for two purposes; one is to improve the transparency of the haptic device by compensating friction components qualitatively and quantitatively, and the other is to reflect the wide-ranged force or torque in large workspace. In the proposed hybrid actuation, the passive actuator is used as the main source of the reflective output, since it has the passivity property in nature so that the safety in interaction and the stability in haptic control can be concurrently guaranteed. The active actuator, which is active in nature, is used either for compensating back-driven components in the haptic system or for providing additional outputs in the haptic reflection larger than the maximum capacity of the passive actuator.
Modeling of giant magnetostrictive actuator based on hysteretic nonlinear theory
Authors: Zhu Zhi-Wen , Liu Yue , Xu Jia , Wang Hong-Li
Published: December 2018

In this paper, a kind of giant magnetostrictive actuator (GMA) model based on hysteretic nonlinear theory was developed. Nonlinear difference item was introduced to interpret the hysteresis phenomenon of GMA. The coupling relationship between magnetic field intensity and frequency was obtained in stepwise multiple regression method to describe the driftage of strain curve. Based on above, the final relationship among strain, magnetic field intensity and frequency was set up. The result of significance test shows that the effects of all of the items in the final model are remarkable, which means that the model can describe the characteristics of GMA in different frequencies well. The new GMA model broadens the region of controlling frequency, and is easy to be analyzed in theory, which is helpful to vibration control.
Simultaneous recording of shadowgrams and schlieren images for the study of plasma assisted aerodynamics
Authors: Machado José Márcio , Shiyou Yang , Abe Nancy Mieko , Passaro Angelo
Published: December 2018

This work describes an optical device for the simultaneous recording of shadowgrams and schlieren images, and some results are presented concerning its applications to the study of plasma assisted flow control in airfoil models. This approach offers many advantages in comparison to other methods, specially because the use of tracer particles (like smoke in wind tunnels) is not required for the experiments, thus avoiding contaminations in the electric discharges or air flows. Besides, while schlieren images reveal the refractive index gradients in the area of study, shadowgrams detect the second order spatial derivatives of the refractive indexes. Therefore, the simultaneous recording of these different images may give interesting information about the phenomena under study. In this paper, these images were used to confirm the existence of vortex structures in the flow induced by corona discharges on airfoil models. These structures are a possible explanation for the effects of drag reduction and lift force increasing, which have been reported in experiments of plasma assisted Aerodynamics.
On the structural parameters of magnetorheological damper
Authors: Dong Longlei , Yan Guirong , Du Yanting
Published: December 2018

A novel magnetorheological (MR) damper is presented in this paper. The check valves of the MR damper are configurated in order that the flow direction of the MR fluid is one-way, and the stretch damping force is greater than the compression damping force. The dynamic model of the damper is established, and the theoretical force-displacement diagram is consistent with the test results, which verifies that the dynamic model of the damper is applicable.
Electromagnetic transient analysis of combined instrument transformer with embedded 3D-finite element
Authors: Cundeva-Blajer Marija , Arsov Ljupco
Published: December 2018

In the paper a thorough electromagnetic transient analysis of a combined instrument transformer will be given. A CAD procedure for transformer optimal design by using a genetic algorithm original program will be accomplished. The transient analysis will be fulfilled for the initial and optimal design as well as for a realised transformer prototype. The transient analysis will be non-linear, since the results from previous FEM-3D electromagnetic field study as well as the non-linearity of the two transformer measurement cores will be incorporated.
Parameter identification of simplified Bouc-Wen model for a MR damper using efficient GA
Authors: Xue Xiaomin , Sun Qing , Zhang Ling , Wu Xiaohong , Zhang Lei
Published: December 2018

Experimental study of the MR damper which is designed and made in our laboratory is introduced in this paper. The experimental results indicate that the mechanical behaviour of the MR damper displays remarkably nonlinear hysteretic characteristics. In order to characterize this nonlinear system, the present study sets out to propose a simplified Bouc-Wen model and then adopt genetic algorithm to identify its parameters. The experimental data of the MR damper responses verify that the proposed approaches are capable of efficient computations and accurate parameter estimation. Also suggested are the implications of the present study on other novel smart dampers.
Mixed fault analysis of 3-phase cage induction motor based on winding function theory
Authors: Woo Kyungil , Rhyu Sehyun
Published: December 2018

This paper studies on the fault analysis of 3-phase cage induction motor with the mixed fault of the static eccentricity and the broken rotor bars at steady state. A mathematical fault model is presented by the coupled magnetic circuit approach. The calculation of winding inductances is derived by means of a winding function theory. The stator current and the torque are obtained by means of the coupled magnetic circuit method and Park's transformation. The characteristics of single fault and mixed fault are analyzed. From the simulation results it is shown that there is its own peculiar frequency component obtained by the spectrum analysis of the stator current in the case of a single fault. But in the case of mixed fault, there is a mutual effect between two faults. From the comparison with FEM results, it is shown that the proposed approach can be simulated to diagnose faults in 3-phase cage induction motor.
Magnetic circuit FEM analysis and optimum design for MR damper
Authors: Yang Baokun , Luo Jinglin , Dong Longlei
Published: December 2018

This paper presents an optimized design of a magneto-rheological damper with finite element analysis. The MR damper is a new type one compared with the traditional type, which is called the parallel disks valve mode. The effects of magnetic field formation mechanism and MR effect formation mechanism on the MR parallel disks valve performance are investigated. Analytical results of the optimized design of the MR damper with different structural parameters and different materials indicated that the simulation values by the finite element method are very close to the measured values and also verifies the reliability of the simulation.
Analysis of non-linear effects on starting characteristics of a single-phase line start permanent magnet motor
Authors: Yu Byoung-Hun , Lee Won-Yong , Kim Byung-Taek
Published: December 2018

This paper deals with starting characteristics of a single-phase line start permanent magnet (LSPM) motor considering nonlinear properties of magnetic materials. To take into account nonlinearity of iron core according to operating states, d-and q-axis inductances are calculated by magneto-static FE-analysis for various currents. The calculated dq-axis inductances are used in the equivalent circuit of a single-phase LSPM motor and dynamic performances are analyzed with 4th order Rung-Kutta method. The results are compared with time-step FE-analysis results and the effects of nonlinearity are discussed.
A study on a pole-changing operation of a single-phase written-pole motor
Authors: Park Seong-Cheol , Kim Dae-Kyong , Kim Byung-Taek
Published: December 2018

This paper deals with design and characteristic analysis of a pole changing written-pole motor (WPM), which is a synchronous motor with self-starting ability. The winding configuration is deliberately determined to get a pole-changing function, and it is confirmed by FEA with time step method. In addition during operation of the exciter, the characteristics of magnetization of magnet and synchronization of a rotor are also analyzed.
The frequency selection of power supply in electromagnetic levitation melting
Authors: Wang Yongqing , Li Lei , Li Xiaojia , Wang Haizhou
Published: December 2018

In the condition of certain electromagnetic levitation coil and spherical sample, according to the expressions of levitation force and absorbed power in magnetic field, the relationship between levitation force, absorbed power and high frequency power supply frequency is established in this paper. In addition, the effect of the power supply frequency on the levitation force of the coil and the absorbed power of the sample is analyzed, and the general rules of frequency parameter selection are confirmed. Finally, a guiding role in the frequency selection of high frequency power supply in electromagnetic levitation melting is played.
3-D magnetic and eddy field analysis based on novel two segments coil design for vacuum interrupters
Authors: Sun Peng , Shao Shuwen
Published: December 2018

In this paper a novel coil axial magnetic contact for vacuum interrupters is designed and its magnetic field distribution has been analyzed. This asymmetric contacts structure have a static contact with two coils in series and a moving contact without any coil. The structure of the moving contact is simplified. Its strength will be enhanced, and its weight will be reduced, which is helpful to raise the breaking speed of the vacuum interrupter. Using finite method the 3-D electrode model has been built and the simulation carried out. With the current value at maximal and zero, the axial magnetic field distribution at static contact surface, at moving surface, and at the middle surface between the static and moving contacts have been calculated. And the phase delay time of the axial magnetic field is considered as well. The simulation results provide that this asymmetric axial magnetic field structure can generate strong and uniform axial magnetic field. The residual magnetic field is small and its phase delay time after the current zero is short.
Field circuit and movement coupled finite element analysis on flameproof induction motor
Authors: Bai Baodong , Yu Qing
Published: December 2018

The field circuit and movement coupled finite element method for the numerical analysis of 2D electromagnetic fields is proposed in the way of studying the electromagnetic fields of the three-phase flameproof induction motor. Numerical results obtained by means of the software of finite element analysis for a typical flameproof induction motor in different operation states such as no-load, static and transient states with load have confirmed positively the feasibility of the proposed method in solving the electromagnetic problems. It is the foundation of the flameproof induction motor for optimal design.
A more accurate and practical formula for AC resistance of single-layer air-core solenoid
Authors: Chen Feng , Zhao Yanzhen , Ma Xikui
Published: December 2018

Based on the formulae for calculating ac resistance of long solenoid and strip conductor, an improved formula for single-layer air-core solenoid was derived. The proposed formula is more accurate and practical by virtue of the asymptotic matching model and the least squares method. Moreover, finite element simulations are performed to illustrate the accuracy of the proposed formula.
A study on characteristics of rotor losses for IPMSM considering slot-pole combination
Authors: Seo Jang-Ho , Jung Hyun-Kyo
Published: December 2018

In this paper, we investigated the effect of slot-pole combination on rotor loss in interior permanent magnet synchronous machine (IPMSM) with distributed armature windings. In order to study the characteristics of the rotor losses, two machines for high-speed operation such as electric vehicle were designed. One is fractional slot winding and the other is conventional one. Based on 2-D time-stepped finite element method (FEM) we analyzed both iron loss and eddy-current loss in the permanent magnet of the machines according to their driving conditions. From the analysis results, it was shown that rotor iron loss and eddy-current loss of PM of machine employing fractional slot-winding is definitely large at load condition.
Study on the dielectric property of composite materials based on electric network
Authors: Cheng Yonghong , Jiang Lili , Hu Dike , Xie Xiaojun , Li Mang , Luo Naidong
Published: December 2018

Dielectric property of materials is one of the most fundamental characters. In recent years, there is an increasing interest in the dielectric properties of composite, which consists of matrix and inclusion materials. The volume ratios, component geometry, distribution types of inclusion determine the performance of composite. In this paper, in order to take the factors mentioned above into account, a cubical model and an ellipsoidal inclusion model which contain variables are selected. This article firstly uses a complex method to discretize the models, and then optimize the discretizition process. After getting the capacitance of every part with basic formula and integral, an electric network is put forward to substitute the original model. It is used to investigate the dielectric property. The relationships between static effective permittivity and the volume ratio, the shape of the inclusion are analyzed. The results obtained by the proposed method are compared with the results got by Maxwell Garnett, logarithmic, Bruggeman and experiment data. The comparison results show the proposed approach has great advantages and different model has specific scope.
Modeling and simulation of direct torque controlled SPMSM Drive incorporating magnetic saturation saliency
Authors: Wang Yi , Zhu Jianguo , Wang Shuhong , Guo Youguang , Xu Wei
Published: December 2018

In this paper a comprehensive nonlinear model of surface mounted permanent magnet synchronous machine (SPMSM) is proposed considering both the structural and the saturation saliencies to enable the numerical simulation of new rotor position detection algorithms. An experiment platform is carried out to test and collect the incremental inductance values varying again the stator current levels and the rotor position. The Least Relative Residual Sum of Square (LRRSS) method is employed in the nonlinear inductance function regression. After experimentally identifying out all the parameters, a nonlinear mathematic model of SPMSM is built up. Furthermore, the direct torque control (DTC) scheme is applied to this new model to verify the model and simulate the machine performance.
Vibration control of the high-TC superconducting levitation synchronous motor
Authors: Murakami Iwanori , Yoshizawa Akinori , Kobayashi Yuusuke , Ando Yoshinori , Yamada Kou , Nagaya Kosuke
Published: December 2018

In this research, we propose the high-TC superconducting levitation synchronous motor that the levitation, the drive, and the vibration suppression are possible with the single disk type rotor composed by some permanent magnets. The center of gravity position is low because this rotor is the single disk structure, and the pitching doesn't occur easily. The displacement of the horizontal direction when the levitation rotor rotates is measured with the laser displacement meter. And, the vibration is controlled by feeding back this whirling speed to an damper. The High-TC Superconducting Levitation synchronous motor with such a vibration suppression mechanism is developed, and utility is verified by the experiment. Motion analysis and the numerical analysis of the force of an damper were done.
Current distribution analysis for high temperature superconducting cable considering hysteresis characteristics
Authors: Wang Shuhong , Qiu Jie , Liu Xinying , Wang Zhixuan , Zhu Jianguo , Guo Youguang , Lin Zhi Wei , Wang Yi , Xu Wei
Published: December 2018

This paper presents a hysteresis model for Type-II high temperature superconductor (HTS) by using simplified Preisach Model, in which the Preisach distribution function μ _k α, β) is determined only based on the B-H limiting loop. The nonlinear dynamic circuit model of the superconductor is established. In the circuit model, the hysteresis inductance and hysteresis loss described by using simplified Preisach Model are deduced. Applying the hysteresis circuit model, the currents flowing in different superconductor layers of high temperature superconducting cable are simulated, as well as the hysteresis loss of the superconducting cable. The simulation results are verified by comparison with the data recorded in literatures. Finally, the influences of hysteresis on superconducting cable are analyzed and discussed.
Analysis on the interaction between laser and MIG plasma
Authors: Li and Zhiyong , Wang Yao , Wang Wei , Wang Xuyou
Published: December 2018

In order to study the interaction between laser and MIG plasma, the radiation of YAG laser-pulsed MIG hybrid plasma is collected with fiber spectrometer. High speed video is also applied to study the coupling effect of laser-MIG hybrid welding plasma. Absorption of laser beam by the plasma is the main reason for the interaction, among which inverse bremsstrahlung process and photoionization are the dominant process. The spatial distribution of spectrum is also acquired to provide experimental base for interaction analysis. The result shows that there is a high radiation intensity zone with great gradient in the center of laser-MIG hybrid plasma. An `ionized duct zone' is formed near the laser acting point. The above coupling effect provides a satisfied explanation for the better bead formation and more stable arc in the laser-MIG hybrid welding process.
Influence of boundary shape on interaction process of plasma jet and liquid media
Authors: Yu Yonggang , Yan Shanheng , Zhao Na , Zhang Qi
Published: December 2018

The effects of boundary shape on the propagation form of the plasma jet in liquid media are studied. The construction and consecutive expansion processes of plasma jet in liquid are recorded by high speed digital camera system. The results indicate that the expansion construction of plasma jet in liquid is a typical Taylor cavity, and the axial expansion velocity of Taylor cavity in stepped-wall chamber is greater than that in cylindrical chamber. Based on the experiments, numerical simulations of the interaction of non-steady plasma jet with liquid media are carried out. The change characteristics of pressure and velocity in plasma jet flow field have been obtained.
Characterization of wear-out of friction bearings with an electromagnetic sensor
Authors: Perrin Stéphane , Mawatari Shingo , Kayata Ryo , Maki Koichi , Miya Kenzo
Published: December 2018

Electromagnetic (EM) sensors, by directly measuring the impeller of a rotating machine, offer a powerful way to detect not only defects on the impeller itself but to indirectly assess the condition of the bearings too, through the measurement of the displacement of the shaft and of the impeller. In this paper, a new method that uses statistical features computed on the time domain signals of a rotating impeller measured with several EM sensors is proposed. It is shown that the proposed method allows the full characterization the wear-out (type and quantitative evaluation of the wear-out) in friction bearings. A real world application of this method is presented.
Research for a new actuator with variable step and large displacement
Authors: Zhang Zhijun , Xu Minglong , Feng Bo , Zhang Xinong
Published: December 2018

A new inchworm-type piezoelectric actuator with round trip, variable step, large displacement is presented in this paper. It has two parts: the clamping structure, the pushing structure. Experiment system with high voltage drivers and closed-loop control system is designed. Dynamic model for piezoelectric actuator is built up. This actuator can move a displacement of± 8 mm. Dynamic performance of the actuator is simulated by the MATLAB Simulink, and the results of simulation is in agreement with that of the experiment in 30 nanometer accuracy demanded.
Design of novel magnetic flux barrier for reducing cogging torque in IPM type BLDC motor
Authors: Yang Byoung-Yull , Hwang Kyu-Yun , Shin Dong-Joo , Kwon Byung-Il
Published: December 2018

This paper introduces a rotor core in an interior permanent magnet type brushless DC motor. The rotor core consists of a rotor surface having a non-uniform air gap and a novel magnetic flux barrier. We show that, in the rotor core, the rotor surface having the non-uniform air gap effectively reduces the cogging torque while the optimized magnetic flux barrier reduces the cogging torque, and increases the average torque and the efficiency.
Artificial-esophagus with peristaltic motion using shape memory alloy
Authors: Miki Hiroyuki , Okuyama Takeshi , Kodaira Shingo , Luo Yun , Takagi Toshiyuki , Yambe Tomoyuki , Sato Takeshi
Published: December 2018

Artificial esophagus of less invasive medical applications utilizing mechanical property of shape memory alloys (SMAs) with peristaltic motion is developed. The artificial-esophagus is composed of two SMA springs, polyvinyl chloride tube, and acrylic plate. The dynamic characteristics of an artificial-esophagus actuator are evaluated in terms of the food transport capacity. Closing pressure and the transport speed have sufficiently realized with human-like qualities. The possibility for fully self-contained artificial-esophagus using SMAs is discussed.
Electromagnetic modelling of blood flow in vessels
Authors: Čáp Ivo , Čápová Klára
Published: December 2018

The paper deals with an electromechanical model of liquid flow in a tube in order to model blood flow in vessels. The present paper deals with detailed mathematical development of a model based on the theory of electrical long line with distributed elements. The detailed derivation of primary parameters of the analogical electric circuit is described. There are presented some results of application of the model like wave impedance and wave vector of the blood pulse wave, which are important for the model application to the blood vessels system diagnosis. The significant parameter of the pulse wave – the pulse wave velocity (PWV) has been evaluated and the calculated values of phase and group velocities in selected vessels have been confronted with physiological data.
Numerical calculation of the eddy current problem in magnetic induction tomography for brain edema
Authors: He W. , Luo H.J. , Song X.D. , Xu Z.
Published: December 2018

Magnetic induction tomography is considered to be valuable in medical application of testing brain edema. In this paper, we use the edge finite element method with electric field intensity E as the vector variable to simulate a multi-channel measuring system based on a real human brain finite element model. In simulation, we change the conductivity of brain edema and the frequency of exciting current to research the performance of the multi-channel measuring system in testing the brain edema.
Magnetic suspension system by flux path control using rotary actuator
Authors: Sun Feng , Oka Koich , Saibara Yuuta
Published: December 2018

This paper proposes a magnetic suspension system using a permanent magnet (PM) and a rotary actuator. In this suspension system, the suspension force is controlled by a variable magnetic flux path mechanism where the flux path is changed by varying the angle of the PM. The PM is magnetized in radial direction and driven by a rotary actuator. This system can change the magnetic polarity of the stator and generate a very small suspension force through rotating the PM to some special angles. Since the fixed cores sustain the gravitational force of the suspended object and the rotary actuator has a larger reducer, this system also can generate a very big suspension force comparing with the input force. In this paper, first the prototype and the principle of this magnetic suspension system are explained. And in order to verify the proposed principle, the IEM (integral element method) analysis and basic experiments for magnetic flux density and attractive force are performed. The model is created, and the numerical simulation is carried out. Finally, suspension experiments are executed, and the results support our proposal.
Research on magnetic force characteristics of the controlled-PM Maglev linear synchronous motor with finite element method
Authors: Du Yumei , Jin Nengqiang , Shi Liming
Published: December 2018

A controlled-PM Maglev system with permanent magnets and electromagnets excitation together can improve the lift/weight ratios, and reduce electromagnetic power consumption at the same air gap compared with a conventional electromagnetic attractive levitation system. It has been proved to be a very effective approach with great potential for application in magnetic levitation system. This paper analyses the magnetic force characteristics of linear synchronous motor in a controlled-PM maglev model vehicle system in our lab with finite element method (FEM), presents the relationship between the magnetic forces and air gap at different current excitation, thrust-angle performance, and experiment results.
A curvature sensor using a solid polymer electrolyte
Authors: Okuyama Takeshi , Otsuki Manabu , Komiya Ryota , Sugoh Nozomu , Tanaka Mami
Published: December 2018

This paper describes a development of a polymer sensor using a solid polymer electrolyte (SPE) film. The sensor has a basic structure that an SPE film is sandwiched between thin carbon films, and conductive tapes are attached on each carbon film. The SPE film has a good flexibility and it is one of the most promising electroactive polymers (EAP) with capability to be used as an actuator and a sensor in air. First a displacement sensor using the SPE film was fabricated. The response to deformation was investigated. Then a curvature sensor using the SPE film is proposed. In experiments, it was found that the proposed sensor is available to measure curvature directly without complex calculations.
Electro-hydraulic control research of hydraulic support hand-control directional valve with the MR fluid base
Authors: Zhao Can , Liu Dandan , Li Huajun , Tang Chunrui
Published: December 2018

By analyzing the driving moment of the hydraulic support hand-control directional valve, this paper presents an electro-hydraulic control method for the directional valve with a magneto-rheological (MR) valve base. Firstly, the theoretical values of the control moment on the feed oil loop and return oil loop of the directional valve are calculated based on the operating principle of the valve and the stress analysis of the control mechanism. Then, the actuator of the directional valve with MR valve base is designed and the mathematical model of its operation moment is established. Simulation and test results show that this method can realize the electro-hydraulic control of the hydraulic support hand-control directional valve, and satisfy the regulation of intrinsic safety.
Open-type magnetic shielding method
Authors: Saito Takeshi
Published: December 2018

The belief for many years has been that magnetic materials should be arranged without any space between them to achieve a sufficient magnetic shielding effect. However, it was determined that a wall made by aligned strips with sizable gaps could achieve almost the same magnetic shielding effect as a wall using the conventional continuous plate method. In this paper, the new method using aligned strips with gaps is called the open-type magnetic shielding method. The open-type magnetic shielding method allows light and air to pass through walls/boxes providing opportunities to improve a wide range of applications. This study reports the process to devise this open-type magnetic shielding method with some experimental data.
The feasibility of MFL inspection for omni-directional defects under a unidirectional magnetization
Authors: Sun Yanhua , Kang Yihua
Published: December 2018

For the drawbacks of present MFL (magnetic flux leakage) testing of omni-directional defects using multidirectional magnetization, a new method of MFL inspection for omni-direction defects under a unidirectional magnetization is proposed. Then, its feasibility is verified by simulations and experiments, leading to a breakthrough of the conventional MFL theory which argues that there is little MFL produced by the defects parallel or nearly parallel to the magnetization direction. Additionally, a method for ensuring a uniform evaluation for the defects with same sizes but different directions is also presented. Finally, some good application cases of the proposed technology were shown.
Static and dynamic responses analysis for 1–3 piezocomposite laminates with Interdigitated Electrodes
Authors: Zhang Hongyan , Bai Changqing , Li Yueming
Published: December 2018

The static and dynamic responses analysis for the 1–3 piezocomposite laminates equipped with Interdigitated Electrodes (IDE) is performed with analytical method. In the static analysis, the solution of the derived governing differential equations is obtained through the power series expansion and Fourier expansion methods. In the dynamic analysis, the governing equations for the transverse vibration are established based on the thin plate theory, and the solutions are obtained through the separation of variables and Fourier expansion methods. The illustrative analysis is carried out to investigate the static and dynamic characteristics of the laminated plates. The numerical results show that, the magnitude of shear curvature gradually increases with the increment of the stiffness anisotropy and the free-strain anisotropy of the piezocomposite and the vibration suppression can be also achieved by adopting a time-dependent control voltage to the IDE of the piezocomposite.
Evaluation of fatigue strength of Me-DLC coating on NiTi shape memory alloy for medical applications
Authors: Shiota Hiroyuki , Takeno Takanori , Miki Hiroyuki , Takagi Toshiyuki
Published: December 2018

The fatigue strength of Me-DLC coating on NiTi shape memory alloy was investigated. Me-DLC was deposited on SMA by radio-frequency chemical vapor deposition and co-sputtering of metal target. The fatigue strength of Me-DLC has been evaluated by applying 1% cyclic bending strain. The surfaces of the coating were observed after bending test by using an optical microscope, a scanning electron microscope and an atomic force microscope. In the result of 1% cyclic bending test, fatigue strength was improved by metal addition. The investigated coating can endure the cyclic bending test up to 10 ^{5} .
A design strategy of structual health management system
Authors: Chang Qi , Yuan Shenfang
Published: December 2018

Health Management System has become a methodological tendency treating the modern complex system in terms of safety and economics. OSA-CBM has been widely accepted as a standard architecture of the Health Management System. According to the architecture, an open and configurable knowledge management system is required to function as the key to the Health Management System. Through the ontology modeling of the domain knowledge, the sharing and reuse of the knowledge can be achieved. Building the related reasoning rules and with the help of reasoner, domain knowledge involved in health management can be inferred. With this knowledge, the related functional agent can be organized into a multi-agent system to achieve the health management task. A strategy of voting mechanism is proposed in data fusion to improve the veracity and reliability of diagnosis. A system of bolt health management system is shown to verify the system and its efficiency.
Characterization of sidewall roughness for silicon microstructures in micro actuator
Authors: Han Guoqiang , Jiang Zhuangde , Jing Weixuan , Gao Jianzhong , Prewett Philip D. , Jiang Kyle
Published: December 2018

Thermal micro actuators are fabricated using deep reactive ion etching (DRIE) technique on silicon on insulator (SOI) substrates. The sidewalls of silicon microstructure in micro actuator are used as optical interfaces with the fibers. Line edge roughness (LER) of reflective sidewalls is essential to device performance. A method is presented through analyzing high-resolution top-down scanning electron microscope (SEM) images to characterize sidewall line edge roughness (LER) of Si microstructures in thermal micro actuator, only conventional SEM scanning technique is required.
The cross-entropy method and its application to minimize the ripple of magnetic levitation forces of a maglev system
Authors: Zhang Wei , Yang Shiyou , Bai Yanan , Machado José Márcio
Published: December 2018

This paper explores firstly the potential of a new evolutionary method – the Cross-Entropy (CE) method in solving continuous inverse electromagnetic problems. For this purpose, an adaptive updating formula for the smoothing parameter, some mutation operation, and a new termination criterion are proposed. The proposed CE based metaheuristics is applied to reduce the ripple of the magnetic levitation forces of a prototype Maglev system. The numerical results have shown that the ripple of the magnetic levitation forces of the prototype system is reduced significantly after the design optimization using the proposed algorithm.
Quantitative NDE of welding defects in lattice sandwich metallic plate by using DC potential drop method
Authors: Zhang Dongli , Chen Zhenmao , Xu Minglong , Lu Tian-Jian
Published: December 2018

Lattice sandwich metallic plate (LSMP) is an important multifunctional material. The strength of LSMP may be significantly affected by defects in its welding joints. In this paper, Direct Current Potential Drop(DCPD) in addition with a sizing indicator is proposed as a quantitative NDE tool to evaluate the welding defects in LSMP. Simulation and experimental results show that the proposed strategy is efficient for the quantitative NDT of welding defects in LSMP.
Enhancing information level in eddy-current non-destructive inspection
Authors: Janousek Ladislav , Smetana Milan , Capova Klara
Published: December 2018

The paper focuses on increasing information level of response signals in eddy-current non-destructive inspection. A new eddy-current detection system is proposed in the study for enhancing quantitative evaluation of an indicated defect. It is composed of three circular inductance coils positioned perpendicularly to each other. The system allows sensing all of the three spatial components of the perturbation electromagnetic field. Thus more complex information about an inspected defect is gained. Numerical simulations are carried out and the results are evaluated to demonstrate capabilities of the new system in reducing the ambiguity of crack sizing using eddy-current non-destructive inspection.
Enhancement of sizing capability of ECT for deep cracks by using split TR probes
Authors: Zuo Yongbin , Chen Zhenmao , Mao Ying , Zhang Jing
Published: December 2018

In this paper, the performance of two probes of split TR structure is evaluated by numerical analysis aiming at the enhancement of sizing capability of ECT for a deep crack. The structures of the two probes are respectively of reflection and transmission type consisting of a rectangular excitation unit and a pancake pickup coil. A modified way is proposed for the reflection type probe to improve the eddy current penetration. Numerical results reveal that the modified reflection type probe and the transmission type probe are promising for the sizing of deep cracks.
Quantitative evaluation of wall thinning in pipe wall using electromagnetic acoustic transducer
Authors: Kosaka Daigo , Kojima Fumio , Yamaguchi Hiroshi
Published: December 2018

This paper aims at a quantitative nondestructive evaluation of pipe wall thinning using an electromagnetic acoustic transducer. Type 304 stainless steels sample specimens that are fabricated by a semi ellipse were provided for our experiments. First, results of measurement and simulation experiments are shown using the provided test samples. The variety of simulation results showed good agreement with laboratory experimental results. Second, the sensitivity of pulse echo signals with respect to corrosion geometry of pipe wall is investigated. Finally, the feasibility studies of our sizing methodology are summarized for evaluating FAC and early LDI test samples.
Characterizing stress concentration by metal magnetic memory signal of H_{p}(x)
Authors: Dong Shiyun , Wang Dan , Xu Binshi , Shi Changliang
Published: December 2018

A novel method for quantitative characterization of stress concentration based on the tangential component of metal magnetic memory (MMM) signal, H_{p}(x) , was studied via fatigue testing and MMM testing of notched plate samples. In this research, the changing regularity of H_{p}(x) signals is found out. A method to calculate stress concentration factor from H_{p}(x) signals is established, and a new conception of magnetic stress concentration factor K_{H} , H_{p}(x)_{max} / H_{p}(x)_{ave} , is put forward to quantitatively characterize stress concentration in mechanical components. The research provides the potential possibility of quantitative inspection for metal magnetic memory testing.
Pulse eddy currents using an integral-FEM formulation for cracks detection
Authors: Preda Gabriel , Rebican Mihai , Hantila Florea Ioan
Published: December 2018

Pulse eddy currents are proposed for detection of cracks in structural conductive, non-magnetic parts. The rectangular pulse accounts for a multi-frequency analysis with the lower harmonics pentrating deeper in the material. An integral-FEM method for simulation of transient eddy-currents and model of defects as zero-thickness, two-dimensional flaws are used. Difference signals peak value depends on crack depth and the peak value moment is delayed for smaller outer defects. The method is effective for defects buried deep under the surface.
MFL testing of omni-directional cracks in steel strip using strong longitudinal magnetization
Authors: Song Kai , Kang Yihua , Sun Yanhua , Qiu Chen , Su Jianke
Published: December 2018

A variety of defects in continuous steel strip may result in accidents. Traditional MFL (Magnetic flux leakage) testing method can lead to large blind area because steel strip is too broad to be rotated. A new MFL testing method that can inspect omni-directional cracks in steel strip is introduced in this paper. This method is characterized basically by the deep saturation state of steel strip generated. The property of inspection is investigated using 3-D finite element method. Waveform configurations of the experimental results agree with that of the theoretical predictions. Automatic inspecting equipment has been developed based on the new MFL method principle.
Development of a novel fast solver for the direct current potential drop method and its verification with nondestructive testing of metallic foam
Authors: Xie Shejuan , Chen Zhenmao , Takagi Toshiyuki
Published: December 2018

A fast forward scheme based on the Finite Element Method (FEM) and databases is proposed and developed for the rapid computation of Direct Current Potential Drop (DCPD) signals under condition of 3D FEM analysis for Nondestructive Testing (NDT) of Metallic Foam to reduce computer burden. Comparison of numerical results of the present method with those of full FEM code and experimental results of metallic foam indicates that the proposed novel fast forward scheme can predict DCPD signals accurately and over 100 times faster.
Simulation and experimental study of remote field eddy current testing on flat conductive plate
Authors: Wang Haitao , Luo Qiufeng , Wang Xin , Tian Guiyun , Xing Lidong , Wang Ping , Li Yong
Published: December 2018

Remote-field eddy current (RFEC) inspection has shown its advantages over the other techniques in Electromagnetic non-destructive evaluation (ENDE) techniques in detection and characterization of deeper defects. In this paper, a new RFEC transducer has been designed for inspection of flat conductive plates, based on numerical simulations using finite element method. Through experimental study, it is concluded that the new transducer has the capability of detecting deep buried defects, and that the phase of RFEC signals have linear relation with the depth of the defects.
Hysteresis phenomena of ultrasonic velocity change in magnetorheological fluids
Authors: Bramantya Muhammad Agung , Takuma Hiroki , Sawada Tatsuo
Published: December 2018

The magnetorheological response of magnetorheological fluids (MRF) results from the polarization induced in the suspended particles by application of an external magnetic field. We proposed a qualitative analysis of these effects by measuring properties of ultrasonic propagation. Hysteresis was appeared when magnetic field increased to and decreased from the certain value, 290 mT in our experiment. The change rate of the ultrasonic wave propagation velocity increased during the increasing process of the external magnetic field. However, it was kept almost the same value during the decreasing process.
Electro-elastic dislocation fields in a piezoelectric sandwich structure
Authors: Nowacki J.P. , Alshits V.I. , Radowicz A.
Published: December 2018

The coupled 2D electro-elastic fields are found in the piezoelectric sandwich structure (substrate-layer-substrate) of unrestricted anisotropy containing the straight-line source parallel to the interfaces. The general line source consists of the four coinciding sources: the line of forces, the charged line, the dislocation line and its electrostatic analogue. The obtained solution is presented in a form of convergent Fourier integral. The integrand is implicitly expressed in terms of the eigenvalues and the eigenvectors of the generalized Stroh matrix. Determination of these eigenvalues and eigenvectors requires additional computing. Specific features of the found fields are analyzed.
Shock wave control by dielectric barrier discharge and arc discharge in a Mach 2.2 cold supersonic airflow
Authors: Wang Jian , Li Yinghong , An Zhiyong , Wang Cheng , Hou Shengli
Published: December 2018

Shock waves in supersonic flows can be effectively controlled by gas discharge plasmas, and thermal mechanism has gained preliminary consensus in the literature. In the present paper, we try to validate the thermal mechanism of shock wave control by gas discharge plasmas experimentally. Surface dielectric barrier discharge (DBD) plasma and surface arc discharge plasma were selected as representatives of low-temperature cold plasmas with weak thermal effect and low-temperature thermal plasmas with strong thermal effect, respectively. An oblique shock wave from a wedge was controlled by these two types of gas discharge plasmas respectively in a Mach 2.2 wind tunnel. Schlieren photography and gas pressure measurement results demonstrated that the cold DBD plasma had no obvious control effect on the shock wave, but the shock wave structure was distinctly changed by the hot arc discharge plasma. Under test condition of arc discharge power 1.3 kW, the start point of shock wave shifted upstream 4 mm, the shock wave angle decreased 8.6% and its strength weakened 8.8%. Therefore, we conclude that only the low-temperature thermal plasmas with substantial heat energy addition to the supersonic flow field have the control abilities on shock wave. This work will provide more evidence on the thermal mechanism of shock wave control by gas discharge plasmas.
Development of cylindrical magnetic gear prototype
Authors: Ando Yoshinori , Ito Masaru , Murakami Iwanori
Published: December 2018

A magnetic gear doesn't have the noise, the vibration and the dust because a magnetic gear transmits power without contact. However, the transmission torque cannot be enlarged. For the current magnetic gear, the diameter of the gear and the centrifugal force grows larger when the transmission torque is increased. When the centrifugal force grows excessively, the possibility of the magnet dispersion increases. A cylindrical magnetic gear has prospects of improvement on these weak points of a past magnetic gear. Therefore the purpose of this research is to develop the cylindrical magnetic gear experimental device.