International Journal of Applied Electromagnetics and Mechanics - Volume Pre-press, issue Pre-press

Authors: Pávó, József | Gyimóthy, Szabolcs | Bálint, Botond | Bilicz, Sándor | Vértesy, Gábor | Tomáš, Ivan

Article Type: Research Article

Abstract: Magnetic flux simulations were utilized in a novel magnetic measurement method performed for the detection of local thinning of ferromagnetic plates. It was shown by numerical simulation, how parameters affect detectability of the defects. Linear relationship was found between the evaluated parameters and size of the artificial slot. Good correlation was found between theoretical and experimental results.

Keywords: Magnetic nondestructive testing, magnetic flux simulation, magnetic adaptive testing

DOI: 10.3233/JAE-171211

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Xu, Jiang | Chen, Guang | Zhou, Jinhai | Li, Yong

Article Type: Research Article

Abstract: Recently, some researchers found that there was a notchfrequency phenomenon when the guided wave propagated in the pre-stressing strand under tension. The notch frequency has a linear relationship with the logarithm of tension. According to their results, a force measurement method for the strand was proposed. However, fatigue damage is often encountered inservice strands. In this paper, we study the effect of fatigue damage on the notch frequency of the pre-stressing strand under tension based on the magnetostrictive guided wave technology. The relationship between the cyclic loading times and the notch frequencies under the same tension is obtained from four …pre-stressing strands. The results show that the notch frequencies are variable with the cyclic loading times. At first, the notch frequency increases slightly, then decreases suddenly, and then increases almost linearly with increasing of the cyclic loading times. Our research indicates that the tension measurement method by using the notch frequency for strands should consider the effect of the fatigue damage. Moreover, the notch frequency can also be employed to evaluate the fatigue damage of strands after 1.85 million cyclic loading times. Show more

Keywords: Notch frequency, fatigue damage, pre-stressing strand, guided wave, magnetostrictive effect

DOI: 10.3233/JAE-171109

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Watanabe, Kota | Taiami, Yuki

Article Type: Research Article

Abstract: Fast liner solvers for shape optimization using a deflation technique are discussed. The optimization method based on evolutionary algorithms such as genetic algorithm requires huge computational cost to evaluate many trial shapes. In this reason, a deflated preconditioned conjugate gradient (PCG) method is introduced so as to reduce the cost of finite element analysis which is used to evaluate the objective function. The deflation technique decomposes the solution into fast and slowly components. The slowly components can be solved by direct methods with low computational cost due to small dimensions. Therefore, the deflated PCC method can improve the convergence. Thus, …the proposed method can reduce the computational cost. Numerical results show that the present method can improve the convergence and reduce the computational cost of optimizations of electromagnetic devices. Show more

Keywords: Deflation method, linear solver, optimization

DOI: 10.3233/JAE-171139

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-7, 2018

Authors: Murakami, Iwanori | Chi, Raymond | Kaneko, Kensuke | Higuti, Tetsuta

Article Type: Research Article

Abstract: Recently, the majority of artificial hearts have been non-pulsatile types. However natural hearts are pulsatile, and the long-term bio-compatibility of the non-pulsatile types has not been confirmed. We developed a linear actuator that can expect to be applied to pulsatile artificial heart. This linear actuator was applied to an electromagnetic pump. It consists of power transmission, tanks, and permanent magnets. We propose a structure to reduce power consumption by a spring. Reduction in power consumption makes possible to downsize the entire apparatus.

Keywords: Electromagnetic pump, linear actuator, artificial heart, halbach array

DOI: 10.3233/JAE-171190

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-11, 2018

Authors: Xia, Yu | Feng, Chendong | Xiong, Yinze | Luo, Yun | Li, Xiang

Article Type: Research Article

Abstract: Additive manufacturing technology has been widely used for the fabrication of porous titanium (Ti) orthopedic implants. Though high porosities and low stiffness of the scaffolds are benefit for bone ingrowth, the compressive strength and fatigue performance of the scaffolds are still necessary for load-bearing applications. In this study, a novel porous scaffold with framework structure was designed and fabricated using selective laser melting process. The mechanical properties of the porous Ti scaffolds were evaluated. The results showed that the compressive strength of the scaffolds possessing framework structure was enhanced significantly with the porosity decreased slightly. In addition to static mechanical …properties, the fatigue properties of the porous Ti scaffolds were also improved via the framework structure. Show more

Keywords: Additive manufacturing, porous titanium, compressive strength, fatigue test, framework structure

DOI: 10.3233/JAE-171197

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2018

Authors: Sasaki, Hidenori | Igarashi, Hajime

Article Type: Research Article

Abstract: This paper presents a new topology optimization of interior permanent magnet (IPM) motors using the genetic algorithm with aid of the deep leaning. The data composed of the rotor shape of an IPM motor and its performance, obtained by a prior topology optimization process, is input to a convolutional neural network (CNN). After the learning process, CNN is shown to provide fairly accurate estimate of the motor performance. During the posterior topology optimization, the finite element analysis (FEA) is carried out only for the limited number of individuals; probability that FEA is performed increases with the motor performance evaluated by …CNN. It is shown that the computing time is reduced to about 1/10 without deterioration of the optimization performance with aid of the deep learning. Show more

Keywords: Topology shape optimization, deep learning, finite element method, IPM motor

DOI: 10.3233/JAE-171164

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2018

Authors: Ye, Chaofeng | Rosell, Anders | Haq, Mahmoodul | Stitt, Erik | Udpa, Lalita | Udpa, Satish

Article Type: Research Article

Abstract: This paper presents an eddy current (EC) probe with orthogonal excitation coils that can change the exciting current direction electrically and tunnel magnetoresistive (TMR) sensor for inspection of stacked CFRP. As CFRP is electrically anisotropic, eddy current excited along the fiber direction is stronger than in other directions. A high sensitivity TMR sensor located at the center of the two orthogonal coils measures the z component of induced magnetic field (Bz) which constitutes the probe signal. The output of the sensor is 0 if the induced currents are symmetric about the sensor. Signals of defects in different orientations depend on …the direction of the exciting current. The operation of the probe is validated using a finite element model. A prototype was built and experimental results from CFRP sample with defects in different orientations are presented and analyzed. Show more

Keywords: Eddy current, CFRP, TMR

DOI: 10.3233/JAE-171193

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-9, 2018

Authors: Xie, Zheng | Shi, Pengpeng | Li, Qun | Chen, Zhenmao

Article Type: Research Article

Abstract: The influence of magnetic field on stress intensity factor at crack tips of a ferromagnetic material is studied in this paper. A method using a sequential coupling algorithm has been applied to solve this coupled problem explicitly. In order to realize the iterative calculation of the stress intensity factor, a semi-analytical solution of the magnetic field perturbation due to structural deformation near by the crack tips is derived at first. The Maxwell stress, the magnetostriction strain and the nonlinear mechanical property of the magnetic material are taken into consideration to cope with the magneto-mechanical coupling effects. Results of perturbed magnetic …field and distribution of magnetostriction strain at the crack tip are obtained and being evaluated quantitatively. Finally, the effects of the applied external magnetic field on stress intensity factor of a crack in a ferromagnetic material are discussed based on the numerical results. Show more

Keywords: Magnetoelastic, magnetostriction effect, stress intensity factor, ferromagnetic material

DOI: 10.3233/JAE-171156

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-11, 2018

Authors: Wang, Zhe | Cui, Ximing | Pu, Haiming | Kang, Yihua

Article Type: Research Article

Abstract: In order to illustrate influence of surface roughness on the energy change of excitation process in thickness measurement of electromagnetic acoustic transducer (EMAT), the change of Lorentz force during the excitation process is analyzed theoretically. A finite element simulation model of EMAT is established with different surface roughness. The distribution of eddy current density and Lorentz force density of different rough surface is discussed. The results show that the eddy current density gets nonuniform due to the irregular profile of the surface. The average value of Lorentz force density decreases with the increase of surface roughness Ra, which makes the …excitation energy of EMAT get weaker. Finally, the experiment results verify the analysis of the theory and finite element simulation. Show more

Keywords: Surface roughness, eddy current density, Lorentz force density, excitation energy change, EMAT

DOI: 10.3233/JAE-171121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-8, 2018

Authors: Theodoulidis, Theodoros

Article Type: Research Article

Abstract: An exact method is presented for calculating the impedance of a coil above a planar conductor with a conductivity profile that varies with depth. The method can be applied to arbitrary continuous profiles and in terms of accuracy or scope it is advantageous over the existing approaches, namely the analytical approach involving the solution of the relevant differential equation in terms of higher transcendental functions and the numerical approach involving the piecewise approximation of the continuous conductivity profile. The method is also very fast and in the context of eddy current nondestructive evaluation it can be readily applied to invert …conductivity profiles from coil impedance measurements. Show more

Keywords: Eddy current testing, analytical modeling, continuous conductivity profile

DOI: 10.3233/JAE-171122

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-7, 2018