Equivalent Circuit in Cauer Form for Eddy Current Field Including a Translational Mover

2020 ◽  
Vol 56 (12) ◽  
pp. 1-7
Author(s):  
Yuji Shindo ◽  
Ryoma Yamamoto ◽  
Kengo Sugahara ◽  
Tetsuji Matsuo ◽  
Akihisa Kameari
2021 ◽  
pp. 136943322110509
Author(s):  
Zhiguo Shi ◽  
Cheng Ning Loong ◽  
Jiazeng Shan

This study proposes an equivalent circuit model to simulate the mechanical behavior and frequency-dependent characteristic of eddy current (EC) damping, with the validations from multi-physics finite element (FE) modeling and dynamic testing. The equivalent circuit model is first presented with a theoretical expression of the EC damping force. Then, the transient analysis with an ANSYS-based FE model of an EC damper is performed. The time-history forces from the FE model are compared with that from the proposed equivalent circuit model. The favorable agreement indicates that the proposed model can simulate the nonlinear behavior of EC damping under different excitation scenarios. A noncontact and friction-free planar EC damper is designed, and its dynamic behavior is measured by employing shake table testing. The experimental observations can be reproduced by the proposed equivalent circuit model with reasonable accuracy and reliability. The proposed equivalent circuit model is compared with the classical viscous model and the higher-order fractional model using a complex EC damper simulated in ANSYS to show the advantages of the proposed model regarding model simplicity and prediction accuracy. A single-degree-of-freedom (SDOF) structure with different EC damping models is further analyzed to illustrate the need for accurate EC damping modeling.


Author(s):  
Toshiyuki Takagi ◽  
Tetsuya Uchimoto ◽  
Hisashi Endo

A computer-aided approach of the eddy current testing (ECT) is described to detect and to size up deep cracks in thick metal structures. A 3D eddy current field analysis based on the finite elements performs designing ECT probes and evaluating the size of crack depth quantitatively. An exhaustive study on the ECT probe specification gives the optimal design of coil elements and their combination. The experimental verification shows that the developed ECT probe employing double exciting coils is capable of detecting crack depth over 10mm from the inspection surfaces. The depth of cracks is quantitatively evaluated from the measured ECT signals with the help of numerical calculation. The results of evaluation profile the crack shapes with fairly high accuracy, supporting our approach.


2013 ◽  
Vol 28 (2) ◽  
pp. 181-193 ◽  
Author(s):  
Marko Jesenik ◽  
Viktor Goričan ◽  
Mladen Trlep

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