Experimental investigation of localized axial winding displacement in a high frequency range for power transformers

2016 ◽  
Author(s):  
Z.W. Zhang ◽  
J. D. Yan ◽  
W. H. Tang ◽  
L. J. Guo ◽  
S. M. Tao
Keyword(s):  
Experimental Investigation ◽  
High Frequency ◽  
Power Transformers ◽  
High Frequency Range ◽  
Frequency Range

Experimental investigation of damage detection in plate-like structure using combined energetic approaches

2018 ◽  
Vol 233 (4) ◽  
pp. 1193-1203
Author(s):  
Ahmed Samet ◽  
Yi Hui ◽  
Mohamed Amine Ben Souf ◽  
Olivier Bareille ◽  
Mohamed Ichchou ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Damage Detection ◽  
Energy Method ◽  
High Frequency ◽  
Excitation Source ◽  
High Frequency Range ◽  
Frequency Range ◽  
High Frequencies ◽  
Frequency Bands ◽  
Different Characteristics

In this paper, an experimental investigation of damage detection in plate-like structure using energetics approaches is presented. Two energetics approaches are developed to localize the damage in structure at low-, medium-, and high-frequency range. The first one is the inverse simplified energy method, which is used for the identification of the excitation source and the detection of damage in medium and high frequencies. The second one is the curvature method, which is used for the damage detection in the low and medium frequencies. The main novelty of this paper is to combine these energetics approaches in order to localize the damage in all frequency bands. Experimental examples with different characteristics of plate were performed for the validation purpose. Results show that the presented methods can detect precisely the defects location in plate-like structures.

Electromagnetic Property of La0.7Sr0.3MnO3/Ag Composite at High Frequency

2015 ◽  
Vol 655 ◽  
pp. 182-185
Author(s):  
Ke Lan Yan ◽  
Run Hua Fan ◽  
Min Chen ◽  
Kai Sun ◽  
Xu Ai Wang ◽  
...  
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
Low Frequency ◽  
Electromagnetic Property ◽  
High Frequency Range ◽  
Frequency Range ◽  
Free Electron Concentration ◽  
Theoretical Simulation ◽  
Electrical And Magnetic Properties ◽  
Three Phase

The phase structure, and electrical and magnetic properties of La0.7Sr0.3MnO3(LSMO)-xAg (xis the mole ratio,x=0, 0.3, 0.5) composite were investigated. It is found that the sample withx=0 is single phase; the samples withx=0.3 and 0.5 present three phase composite structure of the manganese oxide and Ag. With the increasing of Ag content, the grain size of the samples increases and the grain boundaries transition from fully faceted to partially faceted. The permittivity of spectrum (10 MHz - 1 GHz) and the theoretical simulation reveal that the plasma frequencyfpincrease with Ag content, due to the increasing of free electron concentration, which is further supported by the enhancement of conductivity. While for the permeability (μr'), theμr'decrease with the increasing of Ag content at low frequency range (f< 20 MHz), while at the relative high frequency range (f> 300 MHz), theμr'increased with Ag content. Therefore, the introduction of elemental Ag resulted in a higherμr'at the relative high frequency range.

An Impedance-Based Approach for Rods With Shear-Type Damping Layer Treatment

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
P. W. Wang ◽  
D. Q. Zhuang
Keyword(s):  
High Frequency ◽  
Continuous Model ◽  
Damping Coefficient ◽  
System Response ◽  
Traditional Model ◽  
Constrained Layer Damping ◽  
High Frequency Range ◽  
Frequency Range ◽  
Shear Type ◽  
Shear Spring

An impedance-based approach for analyzing an axial rod with shear-type damping layer treatment is proposed. The rod and shear-type damping layer are regarded as two subsystems and both impedances are calculated analytically. The system impedance can be obtained through the impedance coupling between the host rod and the damping layer. The shear-type damping layer is regarded as a shear spring with complex shear modulus. Under the traditional model, the damping coefficient diminishes with the increasing frequency. The paper develops two shear-type damping layer models, including the single degree-of-freedom (SDOF) model and continuous model to predict the behavior of the damping layer. Both damping layer models are compared with the traditional model and the system responses from these models are validated by finite element method (FEM) code COMSOL Multiphysics. Results show that the damping coefficients of both the traditional shear-spring model and SDOF model diminish as the increasing frequency so that the system responses are discrepant with that from COMSOL in the high frequency range. On the other hand, the system response from the continuous model is consistent with that from COMSOL in the full frequency range. Hence, the continuous damping layer model can predict a correct damping coefficient in the high frequency range and this property can be also employed to improve the analysis of the constrained-layer damping treated structures. Finally, the modal loss factor and fundamental frequency of the system with respect to different damping layer thicknesses are presented using the developed approach.

Electromagnetic properties of porous 3D carbon-based structures in high frequency range

2021 ◽  
pp. 76-83
Author(s):  
E.G. Shashkova ◽  
◽  
N.I. Valunets ◽  
M.I. Demidenko ◽  
A.G. Paddubskaya ◽  
...  
Keyword(s):  
High Frequency ◽  
Electromagnetic Properties ◽  
High Frequency Range ◽  
Frequency Range ◽  
Carbon Based

scholarly journals Low-loss Cd-substituted Mg ferrites with matching impedance for high-frequency-range antennas

2020 ◽  
Author(s):  
Gongwen Gan ◽  
Dainan Zhang ◽  
Jie Li ◽  
Gang Wang ◽  
Xin Huang ◽  
...  
Keyword(s):  
High Frequency ◽  
High Frequency Range ◽  
Frequency Range ◽  
Low Loss
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