International Journal of Applied Electromagnetics and Mechanics - Volume 64, issue 1-4

Authors: Park, Juhyeon | Lee, Hoyong | Jung, Gyejo | Lee, Jinyi

Article Type: Research Article

Abstract: A nondestructive testing device, consisting of a scanner and signal processing circuits was developed to detect cracks in turbine disk roots. The scanner consists of a longitudinal feeder and a fir-tree-shaped sensor probe. The feeder inserted the sensor probe along the grooves of the turbine blade attachment. Meanwhile, permanent magnets were placed in opposite direction, to generate a closed magnetic field between the magnetic sensors located on the crests of the sensor probe. The fatigue crack in the turbine disk root occurred in the circumferential direction of the turbine. As a result, magnetic flux leakage was caused by disturbing the …flow of closed magnetic field by permanent magnets. The magnetic flux leakage was measured by a magnetic sensor. The effectiveness of the proposed device has been verified using artificial defects introduced into the turbine disk roots by electric discharge machining. Show more

Keywords: Turbine, disk roots, fatigue, stress, sensor array, magnetic flux leakage, residual magnetization

DOI: 10.3233/JAE-209360

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 525-531, 2020

Authors: Cheng, Wenjie | Deng, Zhikai | Cao, Guangdong | Xiao, Ling | Qi, Huimin | Li, Ming

Article Type: Research Article

Abstract: Aiming at the high speed permanent magnet (PM) rotor with the heat source, this work investigates the analytic solution to the transient temperature field and thermal stress field of the rotor, considering the influence of the forced air cooling of rotor surface on the stress field. Firstly, dimensionless formulation of the transient heat conduction equation including interior heat source is derived, where the axially non-uniform heat convection coefficient and the temperature of main flow region are equivalent to their mean values. Secondly, the Fourier integral transform method is used to solve the dimensionless heat conduction equation. Then, the obtained temperature …field is loaded into the analytical solution of strength, in which three types of stress sources such as interference fit, centrifugal force and temperature gradient are included. Finally, examples are carried out to verify the analytical solutions and relative results are discussed. Show more

Keywords: Thermal stresses, PM rotor, strength, high speed, heat convection

DOI: 10.3233/JAE-209361

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 533-540, 2020

Authors: Zhang, Zhihao | Xu, Jiang | Li, Yong

Article Type: Research Article

Abstract: Failure of the cables can cause a bridge to collapse. Fatigue damage of steel wire is one of the causes of cable failure. In this paper, we study the relationship between the fatigue damage and the group speed of guided waves in the steel wire. The relationship between cyclic loading times and group speed of steel wire is obtained by applying tension to steel wire. The results show that the group speed of guided waves increases linearly before the 6.02 million cyclic-loading times, increases exponentially from 6.02 to 6.97 million times. The curve of the relationship between the group speed …of the guided waves and the number of cyclic loading times can be fitted to an exponential function, and this curve can be used as a calibration curve to evaluate the fatigue damage of steel wire. Show more

Keywords: Group speed, guided waves, fatigue damage, steel wire

DOI: 10.3233/JAE-209362

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 541-547, 2020

Authors: Luo, Yajun | Ji, Linwei | Zhang, Yahong | Xu, Minglong | Zhang, Xinong

Article Type: Research Article

Abstract: The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal …design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance. Show more

Keywords: Electromagnetic isolator, displacement amplifier, negative resistance electromagnetic shunt circuit

DOI: 10.3233/JAE-209363

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 549-556, 2020

Authors: Hu, Chaoyue | Xu, Jiang | Li, Yunfei

Article Type: Research Article

Abstract: The reinforcing bar connected by threaded sleeve is widely used. The end contacting status under the sleeve indicates the tightness of the threaded sleeve connection. In this paper, the feasibility of using magnetostrictive guided wave to detect the end contacting status of the reinforcing bar is studied. Firstly, the propagation characteristic of the wave propagating through the threaded sleeve connection is analyzed. The end contacting status affects the reflection and transmission of the wave. Then, experiments are carried out on a thread-sleeve-connected reinforcing bar. The passing signals of the threaded sleeve connection at an exciting frequency of 30 kHz can be …used to distinguish end contacting status of the reinforcing bar. Additionally, the peak voltage of the passing signal’s first passing wave decreases with the increasing loosening angle of the threaded sleeve connection. The study proves the feasibility of detecting the end contacting status using magnetostrictive guided wave. Show more

Keywords: Reinforcing bar, threaded sleeve connection, end contacting status, magnetostrictive guided wave

DOI: 10.3233/JAE-209364

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 557-564, 2020

Authors: Luo, Yajun | Yang, Fengfan | Ji, Linwei | Zhang, Yahong | Xu, Minglong | Zhang, Xinong

Article Type: Research Article

Abstract: An active vibration control scheme was proposed based on Macro Fiber Composite (MFC) actuators for the bending and torsional vibration control of large flexible lightweight wing structures. Firstly, a finite element modeling and modal analysis of a flexible wing are carried out. Further, the number, type, and location distribution of the MFC actuators bonded on the supported beam of the wing are designed. Then, the actuated characteristics of the two kinds of MFC actuators required for bending and torsional vibration controls was theoretically analyzed. The simulation model of the overall vibration control system was also finally obtained. Finally, through ANSYS …simulation analysis, the vibration control effect of the current control system on the first two-order low-frequency modal response of the wing structure is given. The simulation results show that the proposed active vibration control scheme has specific feasibility and effectiveness. Show more

Keywords: Large flexible wing, modal analysis, active vibration control, macro fiber composite actuator

DOI: 10.3233/JAE-209365

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 565-571, 2020

Authors: Chen, Yuansheng | Gu, Cong | Wang, Hao | Qiu, Jinhao | Zhao, Sunchong

Article Type: Research Article

Abstract: A micro-power-generator is developed with piezoelectric ceramics, which can convert the structural vibration energy generated by wind power into electricity to provide energy for micro-devices such as wireless sensor nodes. The vibration modes of the device are analyzed. The standard interface circuit for piezoelectric energy recovery and LTC3588-1 voltage stabilization circuit are selected, and the hardware circuit of the device is designed. The output voltage and power characteristics of micro-power-generator were analyzed under different loads, frequencies and amplitudes. The experimental results show that under the same wind speed, When the blunt body is a cuboid, the power generation effect of …this device is the best under the optimal load, with the maximum output power of 350.7 μW. Under the same load with the same shape and structure, the load voltage and output power increase with the increase of wind speed. Show more

Keywords: Vortex induced vibration, vibration energy harvest, piezoelectric energy harvest

DOI: 10.3233/JAE-209366

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 573-580, 2020

Authors: Xie, Zheng | Zhao, Yinsong | Li, Qun | Chen, Zhenmao | Uchimoto, Tetsuya | Takagi, Toshiyuki

Article Type: Research Article

Abstract: The influence of strong magnetic field on stress intensity factor of an interface crack is studied in this paper. The nonlinear piezomagnetic property and magnetostriction effect have been taken into consideration in the theoretical analyses. This multi-field coupled problem is solved through a sequential coupling approach. The perturbed magnetization caused by the deformation around the crack is solved under magnetic boundary conditions. After modified by the perturbed magnetization, the initial loads are updated with magnetic forces for iterative calculation. With this strategy, the distributions of the stress and displacement at the crack region approach to the real solution gradually. Numerical …results show that the influence of the external magnetic field on fracture behaviors is not ignorable. For structures with interface crack serving in a strong magnetic field, e.g., the multi-layer welded structures in the Tokamak device, the magneto-elastic coupling effects have to be considered to deal with its fracture problem. Show more

Keywords: Magnetoelastic, magnetostriction effect, stress intensity factor, interface crack

DOI: 10.3233/JAE-209367

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 581-588, 2020

Authors: Yan, Bei | Li, Yong | Ren, Shuting | Hu, Jinhua | Chen, Hongen | Abidin, Ilham Mukriz Zainal

Article Type: Research Article

Abstract: Coated conductive structures play an important role in such industrial fields as aerospace, energy, chemical engineering, etc. Because of the corrosive and hostile environments, the corrosion which is normally hidden under the conductor coating, occurs in the surface of the in-service structure. It poses a severe threat to the integrity and safety of the structure. Therefore, it is imperative to effectively detect and quantitatively evaluate the hidden corrosion via Non-destructive Evaluation (NDE) techniques. Pulse-modulation Eddy Current technique (PMEC) has been identified to be superior to other electromagnetic NDE methods, particularly regarding evaluation and imaging of corrosion. Whereas, the acquired corrosion …images hardly indicate the true opening profile of the corrosion. This hinders the quantitative evaluation of the corrosion. In light of this, in this paper PMEC along with the image processing technique for imaging and evaluation of corrosion in coated conductors is intensively investigated. The image processing technique is proposed based on Theta Map (TM) which is a processing method for quantifying the source parameters of magnetic data that describe the anomalous structure. The validity of PMEC combined with modified TM for profile recognition and assessment of hidden corrosion in nonmagnetic structures is identified via experiments. Show more

Keywords: Electromagnetic non-destructive evaluation, pulse-modulation eddy current inspection, corrosion imaging, Theta Map, profile recognition

DOI: 10.3233/JAE-209368

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 589-596, 2020

Authors: Ito, Yasuaki | Oda, Yoshiho | Kato, Taro | Liu, Xiaojun | Endo, Ayato | Ikeda, Keigo | Narita, Takayoshi | Kato, Hideaki

Article Type: Research Article

Abstract: Thin steel plates are widely used in various industrial products. However, because of the deterioration of surface quality and metal plating that occurs during transport, some problems exist. As a solution to these problems, a noncontact transport of steel plate using electromagnetic force has been proposed. However, side slip or the dropping of the plate may occur. Therefore, we proposed the addition of electromagnetic actuators to control the horizontal motion of levitated steel plates. In this study, we examined the change in the levitation stability during noncontact transport with the addition of positioning control in the horizontal direction or changed …transport conditions. As a result, the application of a magnetic field in the horizontal direction improved the levitation stability of transported thin steel plates in different transport conditions. Show more

Keywords: Electromagnetic levitation control, thin steel plate, vibration control, magnetic field, transportation

DOI: 10.3233/JAE-209369

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 597-605, 2020