scholarly journals Two-Dimensional Ray Mathematical Model of Mechanoelectric Transformations Method for Location of Macrodefects Identification in Solid Dielectric Structures

2020 ◽  
Vol 98 (2) ◽  
pp. 32-42
Author(s):  
R.A. Laas ◽  
◽  
P.N. Khorsov ◽  
A.P. Surzhikov ◽  
A.A. Bespalko ◽  
...  

Method of mechanoelectric transformations can be applied to determine both horizontal position and the depth of a defect in solid nonconductor samples. The method is based on phenomenon of electromagnetic emission in sources of mechanoelectric transformations, such as cracks, voids and impurities of sample structure. It has been shown that method can be used to evaluate integrated stress-strain state of solid dielectric materials. The method is also capable of finding defects is the sample volume, but the robust methodology has to be developed. To develop a methodology of the proper scanning process the experimental setup was created. This work represents ray model of this setup. The model allows us to research pulse characteristics of the response signal considering a variety of excitation signal parameters, defect locations and depths. The model includes dimensions of real sample. Pulse characteristics for response signals of single-period excitation waves with 100 kHz, 300 kHz, and 600 kHz frequencies were obtained. It is shown that increasing the frequency of excitation increases the accuracy of estimating the depth of macrodefects. Time-response characteristics of the signal are most informative.

1992 ◽  
Vol 06 (03) ◽  
pp. 139-144 ◽  
Author(s):  
C.T. CHAN ◽  
K.M. HO ◽  
C.M. SOUKOULIS

Using a plane wave expansion method, we solved the Maxwell’s equations for the propagation of electromagnetic waves inside periodic dielectric materials, and found the existence of photonic band gaps in several classes of periodic dielectric structures.


2013 ◽  
Vol 592-593 ◽  
pp. 529-532
Author(s):  
Robert Macků ◽  
Pavel Koktavý ◽  
Tomas Trčka ◽  
Vladimir Holcman

This paper deals with excess noise sources in dielectric materials. We focus especially on the concrete samples that are frequently tested to ensure information about the reliability and level of degradation. Nevertheless, the testing methods are limited mainly by the proper contact creation, signal detection and noise defined sensitivity. Our efforts are directed to the noise properties assessment. It turns out that the Johnson-Nyquist noise and the 1/f (flicker) noise are generated in the different regions with the different response to the internal or external electric field. In addition the noise analysis is affected by the internal polarization phenomena and the material residual humidity. This issue in connection with the sample geometrical properties and the dielectric noise measurement methodology take part in this paper.


2014 ◽  
Vol 206 ◽  
pp. 107-120 ◽  
Author(s):  
Ugur Cem Hasar ◽  
Joaquim José Barroso ◽  
Musa Bute ◽  
Yunus Kaya ◽  
Mustafa Engin Kocadagistan ◽  
...  

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