International Journal of Applied Electromagnetics and Mechanics - Volume 61, issue 3

Authors: Bafghi, Mohammad Hossein Barzegari | Vahedi, Abolfazl | Mohammad-Alikhani, Arta | Takorabet, Noureddine

Article Type: Research Article

Abstract: Torque transmission along a shaft results in the shaft twisting which is negligible in the conventional motors. However, a long and thin shaft is subject to non-negligible twisting effect. This Phenomenon can affect the electromagnetic performance of the motor. In this article, the shaft twisting effect on the electromagnetic behavior of a flux-switching permanent magnet (FSPM) motor is studied. A model of an FSPM motor is proposed to study the electromagnetic performances of the motor. The electromagnetic torque and twisting rate of each point are calculated along the shaft. Then the model results are compared with finite element analysis results …for a long motor. Show more

Keywords: Shaft twisting, mathematical model, long electric motor, flux switching motor

DOI: 10.3233/JAE-180071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 315-327, 2019

Authors: Zhang, Lei | Zhuan, Xiangtao

Article Type: Research Article

Abstract: Active electromagnetic isolator systems are used to isolate vibration with variable stiffness and damping, flexible controllability, varied control methods and fast response. In order to achieve better vibration isolation performance, an electromagnetic isolator system is designed with small volume and simple structure and the control block diagram with the nonlinear relationships and PID controller is proposed to simulate and verify in this paper. The structure of the electromagnetic isolator system can not only save space, but also provide the controllable electromagnetic force to counteract external disturbances quickly and actively. For improving the vibration isolation performance of the designed electromagnetic isolator …system, a mathematical model which can accurately reflect the relationship between electromagnetic force and coil current and gap is established using structural information and experimental data. A control block diagram of the electromagnetic vibration isolator system containing nonlinear characteristics with PID controller is then designed. The PID control system shows the good performance of active anti-jamming of the designed isolator system. The experimental result demonstrates that the designed electromagnetic isolator system can effectively isolate vibration, and that the control block diagram with PID controller based on the nonlinear system can effectively describe and control the electromagnetic isolator system. The better vibration isolation performance, such as fast response, less overshoot and so on, can be achieved through deliberately designed controllers. Show more

Keywords: Electromagnetic isolator system, vibration control, PID controller, nonlinear system

DOI: 10.3233/JAE-180112

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 329-340, 2019

Authors: Huang, Songling | Sun, Hongyu | Wang, Shen | Wang, Qing | Zhao, Wei

Article Type: Research Article

Abstract: As the focal position of a line-focusing electromagnetic acoustic transducer (LF-EMAT) affects the intensity of the focal signal, we measure the displacement signal and the selection method of the focal line position is then studied in this work to improve the signal intensity and detection precision for a shear-vertical (SV) wave LF-EMAT. We calculate the magnetostatics field and bulk wave propagation utilizing the finite element method (FEM). We simulate the characteristics of the SV wave, and we find that the radiant distance and propagation direction has a great influence on the amplitude of the displacement of the specimen. The superposition …area of SV waves from different sources possesses better focusing ability, and the triangular area (normalized amplitude of the SV waves lower than 10%) near the surface of a specimen should be avoided to be chosen when designing the meander line coils. As for the line-focusing EMAT described in this manuscript, the selection of focal positions for different thickness specimens or detection depth is completely different. Moreover, we perform an experiment to validate the simulation results and lead to a conclusion that the position of the focal point is required to be appropriately close to the excitation coils to enhance the intensity of the signal, while the best focal position should be calculated. Show more

Keywords: EMAT, line focusing, focal position selection, numerical simulation

DOI: 10.3233/JAE-190021

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 341-355, 2019

Authors: He, Tianhu | Ma, Jintao | Li, Yan

Article Type: Research Article

Abstract: In present work, the transient responses of a hollow cylindrical conductor based on the generalized thermoelastic theory with memory-dependent derivative are investigated. The conductor with temperature-dependent mechanical properties is subjected to a thermal shock on its internal surface. The hollow cylindrical conductor is placed in a magnetic field along the axial direction of the cylinder. The effects of memory-dependent derivative and temperature-dependent properties influenced by the variable material property factors on the heat conduction and structural responses are emphatically discussed. The coupled governing equations containing time delay factors and kernel functions, which can be chosen freely according to specific problems, …are solved by the Laplace transform together with its numerical inversion. The distributions of the non-dimensional induced electric field, induced magnetic field, hoop stress, radial stress, temperature and displacement at different values of time delay factors, kernel functions and variable material property factors are obtained and illustrated graphically. Finally, some conclusions are summed up, based upon which guidelines may be provided in the design of a hollow cylindrical conductor working in a thermo-mechanical coupling environment. Show more

Keywords: Memory-dependent derivative, hollow cylindrical conductor, induced electric field, induced magnetic field, Laplace transform

DOI: 10.3233/JAE-180124

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 357-375, 2019

Authors: Huang, Lantao | Zhang, Jing | Zou, Jiahao | Zhou, Yihan | Qiu, Li

Article Type: Research Article

Abstract: Electromagnetic forming (EMF) technology uses pulsed current to generate a pulsed electromagnetic force on metal workpiece to accomplish plastic deformation. It is a promising solution for the room temperature processing of lightweight alloy. Coil design is important to energy efficiency and forming performance of EMF. In order to clarify the effect of the equivalent radius of the drive coil on the forming performance, a simulation study is conducted. The preliminary experiment results show good agreement with results of the simulation, and prove the reliability of the simulation model. Then the process of the electromagnetic sheet free bulging is simulated and …analyzed. It is found that the combined action of the boundary constraint and the inertia effect will influence the maximum forming depth. And the maximum values can be obtained at different systems when the ratio of the equivalent coil radius to the active workpiece radius is about 0.68. Show more

Keywords: Electromagnetic forming, coil design, the maximum forming depth

DOI: 10.3233/JAE-190009

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 377-389, 2019

Authors: Zhang, Yunfeng | Ren, Huan | Zhao, Chenlong | Chen, Jiawen

Article Type: Research Article

Abstract: The three-dimensional model of a lightning rod under a thunderstorm simulated by COMSOL Multiphysics software is established in this paper to study the influencing factors on electric field distortion including the position, height and shape of the lightning rod. In the model, the thunderstorm cloud is equivalent to a plate capacitor; and the building, the lightning rod and the ground are regarded as perfect conductors; whereas their surface potential is zero. The electric field distortion coefficient K is used to measure the influencing parameters on the lightning attachment to the lightning rod. The analysis of model leads to the following …conclusions: influenced by the electric field distortion, a lightning rod at a higher height or at the edge of the building is more likely stuck by the lightning. Considering the effects of the upward connecting leaders in the attachment process, we can further infer that the upward leaders usually start from the tip with greater distortion electric field in the attachment process. However, when the tip of the rod is too sharp, it is often accompanied by the fast attenuation of the electric field, which is not beneficial for the continuous development of the upward connecting leaders. Therefore, in the process of lightning protection design, it is necessary to consider both the position and the height, as well as the shape of the lightning rod in a comprehensive manner. Show more

Keywords: Lightning rod, electric field, distortion coefficient, attachment process

DOI: 10.3233/JAE-180091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 391-401, 2019

Authors: Zhou, Dong | Wei, Min-Xiang | Shi, Li-Hua | Cao, Jie

Article Type: Research Article

Abstract: The mechanism of electromagnetic interference (EMI) is studied for an engine speed acquisition system in this paper. The effect of states and terminal loads is analyzed for the interference signal, which is simulated by using a commercial software. The oscillation of the voltage interference signal is produced by the speed sensor under the radiation of high-altitude nuclear electromagnetic pulse (HEMP), which has been validated by both simulation and experiment. The interference signal can be collected by the speed acquisition system and the normal operation of the engine will be obstructed. The GTEM cell is used for producing the plane wave …for the experiment and the speed acquisition controller is used to test the ability of acquisition for interference signals. Show more

Keywords: Speed acquisition, EMI, HEMP, speed sensor

DOI: 10.3233/JAE-180131

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 403-417, 2019

Authors: Chen, Yuanyang | Bao, Xiaohua | Gao, Ge | Tang, Yizhui

Article Type: Research Article

Abstract: This paper studies the impact of Poloidal Field (PF) coil current disturbance on plasma shape in Experimental Advanced Superconductive Tokamak (EAST). First, the concept of the free-boundary equilibrium problem is studied. Based on the non-rigid plasma model, a free-boundary equilibrium solver developed in MATLAB software is presented to calculate the flux distribution and plasma profile of EAST plasma equilibrium, and the results are validated against the experiments. Second, given a typical double-null plasma equilibrium, the responses of plasma shape to the lower PF coil currents are computed using the orthogonal test method. The dependences of the elongation and triangularity of …plasma shape on PF coil currents are obtained, showing that the currents in PF6 and PF8 have the greatest impact on triangularity and elongation for lower single-null (LSN) divertor configuration, respectively. And for double-null (DN) divertor plasma configuration, PF5 and PF7 play equally important roles due to the up-down symmetry. The conclusions will be useful for the design of EAST plasma shape feedback control. Show more

Keywords: EAST tokamak, plasma shape response, free-boundary equilibrium calculation, orthogonal test method

DOI: 10.3233/JAE-180133

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 419-427, 2019

Authors: Fenercioğlu, Tevfik Ozan | Yalçinkaya, Tuncay

Article Type: Research Article

Abstract: As an integral part of Strapdown Inertial Navigation Systems, ring laser gyroscopes (RLG) are exposed to joint loading conditions where thermal, static and dynamic loads occur simultaneously. The effects of different loading conditions on overall RLG performance should be addressed in parallel for an optimum design. A crucial aspect in this process is the development of the path length controller (PLC), consisting of a mirror, a composite piezo electric bending actuator and other motion transfer elements. This study presents an analogy between the external loading (static, dynamic, thermal, and vibration) on PLC and the RLG signal stability, which has been …studied only partially in the open literature. 5 different PLC designs are analyzed through finite element method and the results are validated experimentally using the composite piezo electric bending actuator by mode-scanning and PZT feedback tests. Obtained results illustrate the axial and the radial displacement (also named mirror tilt) capacity of different PLC designs. Disruptive effects of radial displacement of the PLC mirrors on RLG signal stability are observed. The study is concluded with the classification of different PLC designs for distinctive loading conditions, which is believed to be valuable for the aerospace industry. Show more

Keywords: Path length controller, ring laser gyroscope, finite element analysis, optimization, laser stability, strapdown inertial navigation system

DOI: 10.3233/JAE-190019

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 429-443, 2019

Authors: Chen, Yuansheng | Huang, Qinbin | Wang, Hao | Qiu, Jinhao

Article Type: Research Article

Abstract: Classic Preisach model can precisely describe the hysteresis of piezoelectric stack actuators, but its model identification is relatively complicated. Neural network is easy to be identified with available training algorithm, but it cannot directly describe the multi-valued mapping of hysteresis. A neural-Preisach model was proposed for modeling and control of piezoelectric stack actuators. The neural-Preisach model inherits the advantages of Preisach model and neural network, which can describe the hysteresis and update parameters by training algorithm. A feedforward controller was designed with the inverse neural-Preisach model, and then experiments of tracking control were performed to validate the effectiveness of the …neural-Preisach model. The maximal error, in case of feedforward and PID controller, is reduced by 83.97%, comparing with the case without control. This indicates that control accuracy with hysteresis compensation is greatly improved compared to that without hysteresis compensation. Show more

Keywords: Piezoelectric stack actuators, Preisach model, neural network, hysteresis nonlinearity

DOI: 10.3233/JAE-190086

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 3, pp. 445-459, 2019