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

Authors: Fan, Kangqi | Qu, Hengheng | Cai, Meiling

Article Type: Research Article

Abstract: Ultra-low frequency mechanical excitations are omnipresent in our surrounding environment, but the efficient exploitation of them is generally difficult because they normally drive the widely reported cantilevered harvesters to work under non-resonant conditions. Although the frequency up-conversion strategy has been proposed to mitigate this issue, it usually leads to complicated structures. This paper reports a novel energy harvesting approach based on the twisting vibration of a string-driven rotor. To examine the feasibility of this approach, an electromagnetic energy harvester is designed, which is composed of a lid, a rotor with embedded magnets, a pendant, and a tube with pick-up coils …attached to the outer surface. The rotor is suspended between the lid and the pendant through a piece of string, and then actuated by the ambient excitations through the string. Under the excitations produced by a crank-slider mechanism, the designed harvester can generate useful electric outputs that are proportional to the excitation amplitude, the initial angle between the pendant and lid, and the excitation frequency. Moreover, the harvester can also provide 0.034 mW power when it is periodically pulled by the human hand at approximately 1 Hz. This study demonstrates the potential application of the string-driven rotor in collecting energy from ultra-low frequency excitations. Show more

Keywords: Twisting vibration, ultra-low frequencies, electromagnetic energy harvester

DOI: 10.3233/JAE-209380

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 693-700, 2020

Authors: Tian, Shuxia | Zhang, Penghui | Huang, Liping | Song, Xueqian | Chen, Zhenmao | Liu, Jianxiu | He, Wenbin | Cao, Yang

Article Type: Research Article

Abstract: Hard-point detection is an important content of catenary detection. In this paper, the pantograph-catenary coupling model was established firstly. Then the vertical acceleration of pantograph during operation was calculated by using three-dimensional modeling software and finite element analysis software. The acceleration signal mixed with white noise was filtered by global default threshold, and the hard-point detection feature signal was obtained. Finally, the Hidden Markov Model corresponding to each state of the hard-point was obtained by using the characteristic signal, which verified the feasibility of the Hidden Markov Model for hard-point detection.

Keywords: Hard-point, pantograph and catenary acceleration, white noise filtering, Hidden Markov Model (HMM)

DOI: 10.3233/JAE-209381

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 701-709, 2020

Authors: Rashid, Kashif | Azeem, Muhammad | Kim, Byungtaek

Article Type: Research Article

Abstract: In this paper, a field winding vernier (FWV) machine is proposed to get higher back electromotive force (EMF) than surface permanent magnet vernier (SPMV) machine. First, the magneto motive force (MMF) equation of FWV machine is derived to obtain the requisite field current to produce the same back EMF as SPMV machine. Using the derived equation, the surface current density is also estimated and compared with the maximum allowable current density to examine the possibility of improving the back EMF of the FWV machine and find the slot-pole combination that is advantageous for the FWV structure. Using the obtained information, …three models of SPMV and FWV machines are designed, finite element analysis are performed, and it is verified that proposed FWV machine has the capability of producing higher back EMF than SPMV machine. Show more

Keywords: Field winding, air-gap permeance, permanent magnet, surface current density, vernier machine

DOI: 10.3233/JAE-209382

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 711-719, 2020

Authors: Wang, Li | Chen, Zhenmao

Article Type: Research Article

Abstract: In the nondestructive evaluation for components of key equipment, sizing of natural crack is important in order to guarantee both the safety and efficient operation for large mechanical systems. Natural cracks have complex boundary and there may be electric current flowing through crack faces. If a simple model of artificial notch is used to simulate it, errors often occur in crack depth reconstruction from eddy current testing (ECT) signals. However, if a complex crack conductivity model is used, quantitative evaluation of natural crack will be transformed into a multivariable nonlinear optimization problem and the solution is difficult. In this paper, …based on the relationship between crack parameters and features of multi-frequency ECT signals, a multi-output support vector regression algorithm using domain decomposition for parameters was proposed. The algorithm realized the quantitative evaluation of multiple parameters of crack in turn. Numerical examples with simulated and measured ECT signals were presented to verify the efficiency of the proposed strategy. Show more

Keywords: Quantitative evaluation, natural crack, eddy current testing, support vector regression, multivariable output

DOI: 10.3233/JAE-209383

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 721-728, 2020

Authors: He, Jincheng | Tan, Xing | Tao, Wang | Wu, Xinhai | He, Huan | Chen, Guoping

Article Type: Research Article

Abstract: It is known that piezoelectric material shunted with external circuits can convert mechanical energy to electrical energy, which is so called piezoelectric shunt damping technology. In this paper, a piezoelectric stacks ring (PSR) is designed for vibration control of beams and rotor systems. A relative simple electromechanical model of an Euler Bernoulli beam supported by two piezoelectric stacks shunted with resonant RL circuits is established. The equation of motion of such simplified system has been derived using Hamilton’s principle. A more realistic FEA model is developed. The numerical analysis is carried out using COMSOL® and the simulation results show a significant …reduction of vibration amplitude at the specific natural frequencies. Using finite element method, the influence of circuit parameters on lateral vibration control is discussed. A preliminary experiment of a prototype PSR verifies the PSR’s vibration reduction effect. Show more

Keywords: Piezoelectric shunt damping technology, vibration control, piezoelectric stacks ring

DOI: 10.3233/JAE-209384

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 729-736, 2020

Authors: Kalaiselvan, Kathir Kishan | Ido, Yasushi | Iwamoto, Yuhiro | Toyouchi, Atsushi

Article Type: Research Article

Abstract: Typical particle rotary dampers generate constant torque throughout the cycle of rotation. However, this research is focused on generating angle dependent torque i.e. different torque at different angles. The damper is designed to generate an elevated torque at a specific angle. This can be achieved by employing ferromagnetic particles and by introducing a permanent magnet in the damper. This study is carried out using two major parameters I) base torque which is the measure of damping capacity and II) percentage increase in torque which is the measure of angle dependency. From the experimental investigations, it has been found that I) …base torque increases with packing fraction and rotational speed and decreases conditionally with the amount of carbonyl iron present in the particle while II) percentage increase in torque decreases with packing fraction, remains constant with rotational speed and increases conditionally with the amount of carbonyl iron present in the particle. Show more

Keywords: Particle rotary damper, angle dependency, magnetic elastomer

DOI: 10.3233/JAE-209385

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 737-743, 2020

Authors: Wakayama, Taku | Okuyama, Takeshi | Tanaka, Mami

Article Type: Research Article

Abstract: In this study, a palpation sensor system is developed to detect a lump in a soft object. The developed sensor system consists of a contact part using a bearing, two linear sliders and a 3-axis load cell. While the roller type contact part is scanned against a soft object, reaction force applied to the contact part is measured. Lumps are detected by measuring fluctuation of the reaction force. In experiments, the sensor system is scanned against the samples. From the results, it is found that the lump with a small diameter embedded at a deep position.

Keywords: Palpation, contact force, lump, measurement

DOI: 10.3233/JAE-209386

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 745-752, 2020

Authors: Zhang, Dongli | Wu, Meixian | Chen, Zhenmao | Li, Yong

Article Type: Research Article

Abstract: Usually, the stress corrosion crack (SCC) has a complex shape of non-zero conductivity. Its shape is very difficult to reconstruct accurately by using eddy current testing signals. At present, most defaults being dealt with are shallow cracks with a simple shape, which are not consistent with the actual cases. In order to detect the deep SCC in metal materials quantitatively, a new eddy current probe with capability of deep penetrating is proposed in the paper. Based on the research results of current literature, the conductivity model of deep SCC is established. ANSYS software is used to analyze the influence of …crack inclination, branching position and branch number on eddy current signals to build the equivalent model of SCC. Simulation results show that the new probe is more sensitive to complex SCC than the conventional pancake probe, and can distinguish whether the SCC having branches or not and what the branching position is. The quantitative results of SCC obtained by using a calibration curve show that the detection signals picked up by the new probe can effectively be used to deduce the depth of branching SCC. Show more

Keywords: Eddy current testing, stress corrosion cracking, complex shape, conductivity model

DOI: 10.3233/JAE-209387

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 753-759, 2020

Authors: Chen, Dezhi | Zhang, Yuyong | Yao, Hang | Wang, Yang | Zhao, Wenliang

Article Type: Research Article

Abstract: In this paper, the magnetic field and temperature field of transformer are analyzed, and the influence of temperature on electrical steel sheet is considered. Experiment are supplied to obtain the magnetic properties curves (B-H curves, B-P curves, and magnetic permeability curves of 30QG120), which are required for the accurate FEM (finite element method) simulation setup. Finally, the magnetizing characteristics and temperature distribution of the transformer under different temperatures and loads are studied experimentally. The simulation results of a singlephase transformer are verified by the experimental results.

Keywords: Electrical steel sheet, different temperature magnetizing characteristics, transformer, simulation and experiment

DOI: 10.3233/JAE-209388

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 761-769, 2020

Authors: Mizuana, Yuma | Nakamura, Kenji | Suzuki, Yuma | Oishi, Yuhei | Tachiya, Yuichi | Kuritani, Kingo

Article Type: Research Article

Abstract: Magnetic gears can change output-torque and -speed without any mechanical contacts. Therefore, they have a low acoustic noise and vibration, and their maintainability and reliability are high. Especially, a flux-modulated type magnetic gear is expected to be put into practical use because its torque density is higher than that of other magnetic gears. For the practical use, further improvement of torque and losses is important, especially, reduction of eddy current loss in permanent magnets (PMs) due to asynchronous harmonic magnetic fluxes is necessary. This paper investigates an interior permanent magnet (IPM) structure to improve the efficiency by reducing the eddy …current loss in PMs. In addition, this paper presents a method for increasing torque of the IPM magnetic gear by changing a position of magnetic-bridge. Show more

Keywords: Magnetic gear, flux-modulated type magnetic gear, interior permanent magnet (IPM) structure, eddy current loss

DOI: 10.3233/JAE-209389

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 771-778, 2020