International Journal of Applied Electromagnetics and Mechanics - Volume 52, issue 1-2

Authors: Rymarczyk, Tomasz

Article Type: Research Article

Abstract: New nondestructive methods of the flood embankment dampness were tested. Electrical impedance tomography was used to determine the moisture of the test flood blank on a specially built model. Numerical methods of the shape and the topology optimization were based on the level set representation and the shape differentiation. They made possible to change topology during the optimization. Level set method and Gauss-Newton method have been applied very successfully in many areas of the scientific modelling. These approaches were based on shape sensitivity include the boundary design of the elastic interface. The finite element method has been used to solve …the forward problem. The proposed solution algorithms are initialized by using the topological sensitivity analysis. Shape derivatives and material derivatives have been incorporated with the level set method to investigate the shape optimization problem. The coupled algorithms are a relatively new procedure to overcome this problem. Using the line measurement is very useful to solve the inverse problem in the flood embankment. Show more

Keywords: Electrical impedance tomography, inverse problem, level set method, Gauss-Newton

DOI: 10.3233/JAE-162071

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 79-87, 2016

Authors: Yusa, Noritaka | Sawada, Sakuo

Article Type: Research Article

Abstract: This study proposes a simple and cost-effective method to detect bolt loosening on the basis of low-frequency vibration signals as low as several hertz. Laboratory tests were conducted using M16 bolts connecting two SS400 plates. The bolts were vibrated by external impulse using a test hammer, and their vibrations were measured using accelerometers attached to the nuts holding the bolts. The accelerometers had the lowest measuring frequency of 0.5 Hz, and no high-pass filter was used. The results of the tests show that one can confirm whether or not bolts have been tightened to the rated torque quite clearly in …time domain signals. Subsequent field tests were conducted to evaluate the M42 anchor bolts in a factory, and the results demonstrate the effectiveness of the method. Show more

Keywords: Non-destructive testing and evaluation, vibration, accelerometer, impulse test, frequency

DOI: 10.3233/JAE-162070

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 89-94, 2016

Authors: Cheng, Yuhua | Yin, Chun | Bai, Libing | Bai, Qiuju | Huang, Xuegang | Chen, Kai

Article Type: Research Article

Abstract: This paper employs three neural networks that are BP, RBF and PNN for rolling bearing fault diagnosis and compares their performance. The preprocessed vibration signals of rolling bearing provide fused feature vectors after the process of wavelet package decomposition and feature fusion. Then the fused feature vectors serve as the inputs of networks. The fault diagnostic aims to recognize health condition, fault types and fault severity of rolling bearings. The simulation results demonstrate that BP has the best accuracy and very complex computation efforts, and RBF has the fastest classification with the lowest precision. Meanwhile, PNN achieves perfect accuracy and …speed that can be received. Show more

Keywords: Fault diagnostics, rolling bearings, feature fusion

DOI: 10.3233/JAE-162080

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 95-102, 2016

Authors: Wang, Cheng | Wang, Jianying | Lai, Xiongming | Zhong, Bineng | Luo, Xiangyu | Ying, Hui | Yan, Guirong | Chen, Weibin | Li, Jing

Article Type: Research Article

Abstract: Because excellent properties of the fixed-point iteration algorithm of fast independent component analysis algorithm (FastICA) and better statistical properties of negative entropy and Newton iteration, a FastICA effectively combining negative entropy and Newton iteration for OMA is put forward in this paper. Modal parameter identification results on simulation data of beam show that this method could identify the main modal vibration modes and natural frequencies correctly and efficiently only from measured signals of stationary random vibration response and more robustness than gradient descent and information maximization based ICA for OMA.

Keywords: Operation modal analysis, natural frequencies, mode shapes, fast independent component analysis, negative entropy, Newton iteration

DOI: 10.3233/JAE-162201

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 103-111, 2016

Authors: Motozawa, Masaaki | Takeda, Kosuke | Kawaguchi, Yasuo | Sawada, Tatsuo | Fukuta, Mitsuhiro

Article Type: Research Article

Abstract: Forced convective heat transfer of turbulent magnetic fluid flow is remarkably suppressed by applying magnetic field. Detailed investigation of this suppression of turbulent heat transfer of magnetic fluid was carried out experimentally in this study. The result shows that the suppression of heat transfer becomes strong by applying stronger magnetic field, but is saturated at a certain strength of magnetic field. This suppression depends on not only magnetic field intensity but also flow condition. For generalization of the suppressed heat transfer characteristics of turbulent magnetic fluid flow by applying magnetic field, we proposed Mh number which is defined by …Re divided by a root of magnetic field intensity normalized by saturated magnetization of magnetic fluid. It is found that suppressed heat transfer of magnetic fluid almost linearly increases with increasing Mh number. Show more

Keywords: Magnetic fluid, forced convective heat transfer, turbulence

DOI: 10.3233/JAE-162183

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 113-120, 2016

Authors: Ido, Yasushi | Yokoyama, Hiroki | Nishida, Hitoshi

Article Type: Research Article

Abstract: Magnetorheological fluids containing nanometer size needle-like nonmagnetic particles whose long axis is 194 nm and aspect ratio is 8.3 are prepared as new magnetic functional fluids. Viscous properties of the fluids are investigated experimentally. Shear stress and viscosity coefficient are measured by using the rheometer which has the additional equipment for measurement in the presence of magnetic field. When the total volume fraction of the particles in the fluid is constant (0.30), larger amount of needle-like particles in the fluid gives larger viscosity in the absence of magnetic field. In the contrast, the viscosity and shear stress of the fluid …containing 4% needle-like nonmagnetic particles and 26% micrometer sphere magnetic particles take large value than those of other fluids in the presence of magnetic field. Show more

Keywords: Magnetorheological fluid, needle-like particle, viscosity, damping force, magnetic interaction

DOI: 10.3233/JAE-162214

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 121-127, 2016

Authors: Sudo, Seiichi | Takahashi, Kazuya | Nishiyama, Hideya

Article Type: Research Article

Abstract: This paper is concerned with the magnetic fluid surface instability produced by the external alternating magnetic field with lower strength amplitude. Periodic disintegration and reconnection of magnetic fluid bridge between two small permanent magnets were studied with a high-speed video camera analysis system. Disintegration and connection of the liquid bridge were generated by the external alternating magnetic field produced by the Helmholtz coil. The surface shape of magnetic fluid bridge was changed by the external field every moment. The details of surface phenomena on magnetic fluid bridge were revealed. The relation between the surface shape variation and the external magnetic …field was discussed with the Bond numbers. Show more

Keywords: Magnetic fluids, ferrohydrodynamics, surface instability, alternating magnetic field

DOI: 10.3233/JAE-162223

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 129-136, 2016

Authors: Maschio, Alvise | Bernardo, Enrico | Desideri, Daniele | Marangoni, Mauro | Ponsot, Inès | Pontikes, Yiannis

Article Type: Research Article

Abstract: Shielding effectiveness measurement, up to the GHz range, of construction materials with different compositions is an important issue. In this paper a coaxial waveguide, originally developed for thin films, is proposed as a simple device able to perform measurements on test samples with a thickness of a few millimetres. A calibration of the test system, with length extended of 5 mm, has been done both with a theoretical evaluation and an experimental measurement. Data obtained with construction materials of current interest for research are presented. With respect to similar systems reported in literature, where data up to 1.5 GHz are …shown, this system has proven to be appropriate for measurements up to 3 GHz without too stringent tolerances in the sample geometry and without contact problems. Moreover, with inorganic polymers test samples, a clear relation between shielding effectiveness and heating temperature of the material has been observed. Show more

Keywords: Coaxial waveguide, construction materials, shielding effectiveness

DOI: 10.3233/JAE-162089

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 137-144, 2016

Authors: Jin, Junjie | Duan, Zhenyun | Sun, Feng | Li, Qing | Xia, Pengpeng | Jin, Jiaqi | Oka, Koichi

Article Type: Research Article

Abstract: The parallel permanent magnetic suspension system using flux-path control is composed of a servo motor, a radially magnetized disk magnet, and a pair of magnetizers. Establishing an accurate mathematical model is difficult owing to the system's special structure and nonlinear characteristics. To acquire an accurate mathematical model, an autoregressive exogenous (ARX) model identification method is applied to the system. First, the system input and output data are acquired from the suspension experiment. Then, an ARX model is established utilizing the data from the system identification method. Lastly, the relevant simulations and experiments are carried out to verify the validity of …the ARX model. The results show that the simulation data with the ARX model closely agree with the test data obtained from the same controller. This model identification method can provide a better way to acquire a more accurate mathematical model for improving the controller. Show more

Keywords: Permanent magnetic suspension, model identification, ARX model

DOI: 10.3233/JAE-162027

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 145-152, 2016

Authors: Kato, Taro | Suzuki, Ryosuke | Narita, Takayoshi | Kato, Hideaki | Yamamoto, Yoshio

Article Type: Research Article

Abstract: In recent years, micro-compact electric vehicles have been developed and actively marketed, and has become popular as a new short-distance transfer mobility tool. While micro-compact electric vehicles do not have generate an engine sound, road and wind noises cause interior noise, and have a large impact on user comfort in the interior space. Recently the use of interior noise reduction by ANC has been used in the automobile industry. In this study, we propose a system whereby a giant magnetostrictive actuator is installed on the front window of a micro-compact electric vehicle to actively cut interface vibration noise, i.e., road …noise, transmitted to the interior of the vehicle. In the experiment, we used an enclosure to simulate the interior of a vehicle and investigated the installation position of the giant magnetostrictive actuator to study the vibration characteristics of a window plate. Show more

Keywords: Active noise control, giant magnetostrictive actuator, boundary surface vibration

DOI: 10.3233/JAE-162035

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 1-2, pp. 153-160, 2016