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Wyszukujesz frazę "defect characterization" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Characterization of material defects using active thermography and an artificial neural network
Autorzy:
Dudzik, S.
Powiązania:
https://bibliotekanauki.pl/articles/221055.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active thermography
non-destructive testing
defect characterization
neural networks
Opis:
In the paper a method using active thermography and a neural algorithm for material defect characterization is presented. Experimental investigations are conducted with the stepped heating method, so-called time-resolved infrared radiometry, for the test specimen made of a material with low thermal diffusivity. The results of the experimental investigations were used in simulations of artificial neural networks. Simulations are performed for three datasets representing three stages of the heating process occurring in the investigated sample. In this work, the simulation research aimed to determine the accuracy of defect depth estimation with the use of the mentioned algorithm is descibed.
Źródło:
Metrology and Measurement Systems; 2013, 20, 3; 491-500
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of thinning of homogeneous material using active thermography and classification trees
Autorzy:
Dudzik, Sebastian
Dudek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1848987.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active thermography
classification tree
defect detection and characterization
material thinning detection
Opis:
Active thermography is an efficient tool for defect detection and characterization as it does not change the properties of tested materials. The detection and characterization process involves heating a sample and then analysing the thermal response. In this paper, a long heating pulse was used on samples with a low thermal diffusivity and artificially created holes of various depths. As a result of the experiments, heating and cooling curves were obtained. These curves, which describe local characteristics of the material, are recognized using a classification tree and divided into categories depending on the material thickness (hole depths). Two advantages of the proposed use of classification trees are: an in-built mechanism for feature selection and a strong reduction in the dimensions of the pattern. Based on the experimental study, it can be concluded that classification trees are a useful tool for the thinning detection of homogeneous material.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 89-105
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-level approach for solving the inverse problem of defects identification in Eddy Current Testing - type NDT
Autorzy:
Putek, P.
Crevecoeur, G.
Slodička, M.
Gawrylczyk, K.M.
Van Keer, R.
Dupré, L.
Powiązania:
https://bibliotekanauki.pl/articles/140340.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
charakterystyka wad
elektromagnetyczny problem odwrotny
problem odwrotny
algorytmy optymalizacji
algorytmy dwupoziomowe
badanie wiroprądowe
analiza wrażliwości
defect characterization
electromagnetic inverse problem
two level optimization algorithms
eddy current testing method
sensitivity analysis
Opis:
This work deals with the inverse problem associated to 3D crack identification inside a conductive material using eddy current measurements. In order to accelerate the time-consuming direct optimization, the reconstruction is provided by the minimization of a last-square functional of the data-model misfit using space mapping (SM) methodology. This technique enables to shift the optimization burden from a time consuming and accurate model to the less precise but faster coarse surrogate model. In this work, the finite element method (FEM) is used as a fine model while the model based on the volume integral method (VIM) serves as a coarse model. The application of the proposed method to the shape reconstruction allows to shorten the evaluation time that is required to provide the proper parameter estimation of surface defects.
Źródło:
Archives of Electrical Engineering; 2011, 60, 4; 497-518
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kontrast filtrowany w charakteryzacji wad materiałowych metodą aktywnej termografii
Filtered contrast in defect characterization using active infrared thermography
Autorzy:
Gryś, S.
Minkina, W.
Powiązania:
https://bibliotekanauki.pl/articles/152646.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
badania nieniszczące
aktywna termografia
charakteryzacja defektów
propagacja rozkładów
symulacja Monte Carlo
nondestructive testing
active thermography
defect detection and characterization
propagation of distributions
Monte Carlo simulation
Opis:
W artykule przedstawiono możliwości zastosowania "kontrastu filtrowanego" do wykrywania i charakteryzacji defektów w materiale metodą aktywnej termografii. Do wyznaczenia "kontrastu filtrowanego" nie jest wymagana znajomość obszaru referencyjnego bez defektu oraz jest mniej wrażliwy na niejednorodność napromienienia powierzchni materiału w porównaniu do klasycznych rodzajów kontrastów cieplnych. Eksperyment przeprowadzono na stanowisku wyposażonym w kamerę ThermaCAM PM 595 oraz kartę rejestracji danych. Oszacowano wpływ parametrów cieplnych badanego materiału i defektu oraz parametru filtru wygładzającego, niezbędnego do implementacji idei kontrastu filtrowanego, na niepewność estymacji głębokości defektów. W analizie zastosowano zasadę propagacji rozkładów prawdo-podobieństwa i symulację Monte Carlo.
The paper presents the possibility of the use of new kind of thermal contrast in subsurface defects detection [1,3-6]. It allows detecting defects taking advantages [2,6] of an active thermography - Table 1. In opposition to known definitions of the thermal contrast [1], a defect-free area is no necessary and this contrast is less sensitive to nonuniformity of heat disposal to the material surface. The measurements were per-formed on a setup presented in Fig. 1 [7]. A special sample of Plexiglas was made with bottom-holes simulating defects - Figs 2 and 3. The material parameters - Table 2, were taken from [1]. The step heating was chosen as heat excitation. Exemplary, raw and processed thermograms for symmetrical and asymmetrical heat disposal are shown in Figs 4 and 5. The influence of the parameter B of the smoothing filter, thermal parameters of the tested material and defect on expanded uncertainty of determination of defect depth were analyzed. Due to significant complexity of the model the numerical method, i.e. Monte Carlo simulation was applied. According to this procedure [9,10] an expectation and 95% coverage intervals are presented in Tab 4 and 5. In the Table 6 there is fixed if the 95% coverage interval contains the true value of depth. For the inspected sample, B=10, and assumed accuracy of evaluation of diffusivity [8] of Plexiglas, the accuracy of the method does not exceed 20%. The optimal value of B corresponds to the diameter of defects. This aspect will be examined in further work.
Źródło:
Pomiary Automatyka Kontrola; 2010, R. 56, nr 8, 8; 893-896
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Imaging methods of detecting defects in photovoltaic solar cells and modules: a survey
Autorzy:
Maziuk, Maurycy
Jasińska, Laura
Domaradzki, Jarosław
Chodasewicz, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/27311747.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
solar cells
defects
photovoltaic cell characterization
defect imaging
electroluminescence
photoluminescence
Opis:
In pursuit of increased efficiency and longer operating times of photovoltaic systems, one may encounter numerous difficulties in the form of defects that occur in both individual solar cells and whole modules. The causes of the occurrence range from structural defects to damage during assembly or, finally, wear and tear of the material due to operation. This article provides an overview of modern imaging methods used to detect various types of defects found in photovoltaic cells and panels. The first part reviews typical defects. The second part of the paper reviews imaging methods with examples of the authors’ own test results. The article concludes with recommendations and tables that provide a kind of comprehensive guide to the methods described, depending on the type of defects detected, the range of applicability, etc. The authors also shared their speculations on current trends and the possible path for further development and research in the field of solar cell defect analysis using imaging.
Źródło:
Metrology and Measurement Systems; 2023, 30, 3; 381--401
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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