Temat: digital image correlation

Skocz do pozycji: 1.

Tytuł:: An uncertainty propagation in developed vision based measurement system aided by numerical and experimental tests
Analiza propagacji niepewności w opracowanym wizyjnym systemie pomiarowym wspomagana przez testy numeryczne i eksperymentalne
Autorzy:: Kohut, P.
Holak, K,
Martowicz, A.
Tematy:: digital image correlation
homography mapping
vision system; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/281737.pdf Link otwiera się w nowym oknie
Opis:: In the paper, the vision-based method of static in-plane deflection measurement of a structure is presented. Displacements of measurement points of the structure under the load are computed by means of the normalized digital image correlation coefficient. The application of the homography transformation enables the deflection field to be computed from two images of the structure acquired from distinct points in space. The scale coefficient calculation and marker matching algorithms have been introduced in order to increase the level of automation of the method. The paper presents the results of numerical investigations of the uncertainty propagation in the proposed algorithms. The qualitative comparison of the numerical data and the results of the experiment have been shown.
W pracy przedstawiono wizyjną metodę pomiaru statycznego ugięcia konstrukcji. Przemieszczenia punktów pomiarowych wyznaczane są z wykorzystaniem znormalizowanego współczynnika korelacji wzajemnej. Zastosowanie przekształcenia homograficznego umożliwiło pomiar pola przemieszczeń na podstawie fotografii konstrukcji wykonanej z dowolnego punktu przestrzeni. W celu zwiększenia stopnia automatyzacji metody wprowadzono algorytmy wyznaczania współczynnika skali oraz dopasowania znaczników. W pracy zaprezentowano wyniki symulacji numerycznych propagacji niepewności w proponowanym algorytmie. Pokazano wyniki jakościowego porównania danych symulacyjnych i wyników eksperymentalnych.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Mechanical characterization of orthotropic elastic parameters of a foam by the mixed experimental-numerical analysis
Autorzy:: Chuda-Kowalska, M.
Gajewski, T.
Garbowski, T.
Tematy:: orthotropic elastic foams
digital image correlation
inverse analysis; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/279786.pdf Link otwiera się w nowym oknie
Opis:: Different kind of foams, usually made from polymers, metals, ceramics, glass, etc. have been widely used in various branches of civil engineering since the 80s. The most common are polyurethane foams. Since their role in construction nowadays is not only to act as a thermal barrier but also to take some of loads, the engineers need to know also their mechanical properties. This implies that manufacturers or designers must perform a number of laboratory tests in order to find a set of substantial parameters of this particular material. Due to noticeable orthotropic behavior of foams, one needs to carry out several laboratory tests to identify elastic properties only. Here, an enhanced testing methodology is proposed to reduce the number of tests required for characterization of elastic orthotropic properties of foams. By combining the advanced measurement techniques, non-traditional experimental setup, numerical modeling and inverse analysis one can capture all nine elastic properties from just two or three tests. In the paper, full experimental and numerical procedures are presented and validated by noisy pseudo-experimental data.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation
Autorzy:: Khoo, S.-W.
Karuppanan, S.
Tan, C.-S.
Tematy:: surface deformation
strain measurement
two-dimensional digital image correlation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221852.pdf Link otwiera się w nowym oknie
Opis:: Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Particle shape effect on macroscopic behaviour of underground structures: numerical and experimental study
Autorzy:: Szarf, K.
Combe, G.
Villard, P.
Tematy:: discrete element method
particle shape
underground pipe
digital image correlation; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/178734.pdf Link otwiera się w nowym oknie
Opis:: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods. Moreover, Discrete Element approach is able to provide information about the grain–grain and grain–structure interactions at the microscale. This paper presents numerical and experimental investigations of flexible buried pipe behaviour with focus placed on load transfer above the buried structure. Numerical modeling was able to reproduce the experimental results. Load repartition was observed, being affected by a number of factors such as particle shape, pipe friction and pipe stiffness.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The possibility of DIC system application in numerical models updating
Autorzy:: Turoń, Barabara
Miller, Bartosz
Tematy:: Digital Image Correlation
DIC system accuracy
optimization
updating of numerical models; Pokaż więcej
Wydawca:: Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Powiązania:: https://bibliotekanauki.pl/articles/390768.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the results of updating of numerical models of the rectangular steel plate members in a plane state of stress, the updated parameter was a support length. Three different members loaded in a static or dynamic way were analyzed. The article shows examples of purely numeric updating. The data used to the update of numerical models was obtained from numerical simulations and it corresponds to the data, which can be measured by using the Digital Image Correlation (DIC) system. The main aim of the paper is to check the possibilities of the DIC system application in updating of numerical models.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Non-destructive detection of high-strength wind turbine bolt looseness using digital image correlation
Autorzy:: Xie, Wei-Guo
Zhou, Peng
Chen, Li-Yun
Gu, Guo-Qing
Wang, Yong-Qing
Chen, Yu-Tao
Tematy:: bolt looseness detection
digital image correlation
loosening angle
preload force loss; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/58973588.pdf Link otwiera się w nowym oknie
Opis:: Looseness of high-strength wind turbine bolts is one of the main types of mechanical failure that threaten the quality and safety of wind turbines, and how to non-destructively detect bolt loosening is essential to accurate assessment of operational reliability of wind turbine structures. Therefore, to address the issue of looseness detection of high-strength wind turbine bolts, this paper proposes a non-destructive detection method based on digital image correlation (DIC). Firstly, the mathematical relationships between the in-plane displacement component of the bolt’s nut surface, the bolt’s preload force loss and the bolt loosening angle are both deduced theoretically. Then, experimental measurements are respectively conducted with DIC with different small bolt loosening angles. The results show that the bolt loosening angle detection method based on DIC has a detection accuracy of over 95%, and the bolt’s preload force loss evaluated by the deduced relationship has a good agreement with the empirical value. Therefore, the proposed DIC-based bolt loosening angle detection method can meet the requirements of engineering inspection, and can achieve quantitative assessment of preload forces loss of wind turbine bolt.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical simulation of shear slitting process of grain oriented silicon steel using sph method
Autorzy:: Bohdal, Ł.
Tandecka, K.
Kałduński, P.
Tematy:: shear slitting
smoothed particle hydrodynamics
grain oriented silicon steel
digital image correlation; Pokaż więcej
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Powiązania:: https://bibliotekanauki.pl/articles/387439.pdf Link otwiera się w nowym oknie
Opis:: Mechanical cutting allows separating of sheet material at low cost and therefore remains the most popular way to produce laminations for electrical machines and transformers. However, recent investigations revealed the deteriorating effect of cutting on the magnetic properties of the material close to the cut edge. The deformations generate elastic stresses in zones adjacent to the area of plastically deformed and strongly affect the magnetic properties. The knowledge about residual stresses is necessary in designing the process. This paper presents the new apprach of modeling residual stresses induced in shear slitting of grain oriented electrical steel using mesh-free method. The applications of SPH (Smoothed Particle Hydrodynamics) methodology to the simulation and analysis of 3D shear slitting process is presented. In experimental studies, an advanced vision-based technology based on digital image correlation (DIC) for monitoring the cutting process is used.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Non-uniform illumination correction based on the retinex theory in digital image correlation measurement method
Autorzy:: Gu, G.
She, B.
Xu, G.
Xu, X.
Tematy:: digital image correlation (DIC)
non-uniform illumination correction
retinex theory
deformation measurement; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173506.pdf Link otwiera się w nowym oknie
Opis:: Digital image correlation is a well-known optical measurement method for full-field deformation and strain measurements. The quality of speckle images used in digital image correlation calculation can directly affect the measurement accuracy of digital image correlation. In most practical measurement circumstances, a uniform illumination environment is usually required to illuminate the detected object in order to capture speckle images upon different deformed states with uniform background intensity. However, the tested object becomes so large that the adopted light source cannot cover all the interested area with uniform illumination, and the speckle images acquired by CCD camera may have non-uniform background intensity distributions. In this paper, the influence of non-uniform illumination is first analyzed in detail by means of a comparison of experimental results of digital image correlation using speckle patterns with both uniform and non-uniform intensity distributions. Then, a new correctional method based on the combination of the basic retinex theory and the illumination formulae of a point light source is proposed. Finally, a real experiment with non-uniform illumination is implemented to verify the effectiveness of this method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Determination of In-Plane Shear Properties of Laminate with V-Notch Rail Shear Test and Digital Image Correlation
Autorzy:: Karny, Maciej
Tematy:: digital image correlation
in-plane shear
thermoplastic laminates
v-notch rail shear; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Powiązania:: https://bibliotekanauki.pl/articles/36405939.pdf Link otwiera się w nowym oknie
Opis:: This article presents the results of the application of Digital Image Correlation (DIC) to measurements of in-plane shear modulus and strength of three different carbon fiber reinforced laminates. Three different approaches to shear strain calculations via DIC are evaluated and compared with standard strain gage measurements. Calculation of shear strain based on averaging DIC strain values of strain gages area in most cases yielded results closest to strain gages, while measurements based on single point strain measuring differed the most from strain gages. These results are attributed to shear strain distribution in the center area of the specimen. Thermoplastic matrix fabric reinforced composite had the lowest shear strength at 5% of shear strain, but the highest ultimate shear strength and strain at failure. Of thermosetting materials, laminate reinforced with unidirectional carbon fiber had shear modulus about 10% lower, than fabric reinforced laminate, but higher ultimate strength and strain at failure. This behavior is attributed to the presence of weaves in fabric reinforcing the laminate, causing shear stiffening of the material, but lowering its ability to deform under shear loading.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Analiza niepewności pomiarów w stereowizyjnym układzie obserwacji
Measurement uncertainty analysis in stereo vision system
Autorzy:: Garbacz, P.
Tematy:: inspekcja optyczna
układ stereowizyjny
cyfrowa korelacja obrazów
optical inspection
stereovision
digital image correlation; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Technologii Eksploatacji - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/256859.pdf Link otwiera się w nowym oknie
Opis:: W artykule przedstawiona została analiza niepewności pomiarowej dla stereowizyjnego układu obserwacji. Przeprowadzono przegląd stosowanych technik ilościowej oceny niepewności tej metody. Przeprowadzono analizę czynników wpływających na wielkość błędów, wynikających zarówno z cyfrowej korelacji obrazów, jak również procesu rekonstrukcji 3D, z uwzględnieniem procesu kalibracji kamery. Oszacowano niepewność pomiarową dla przykładowej konfiguracji systemu.
This paper presents measurement uncertainty analysis in stereo vision system. Error sources are divided into two categories: correlation errors and 3D reconstruction errors, including camera calibration influence. Errors related to the measurement devices, working environment and the digital image correlation principle itself are listed. The effect of various parameters of the stereo vision system on 3D measurement accuracy has been presented. Quantitative error analysis has been described and the uncertainty of locating the 3-D space points was estimated for an experimental setup of the stereovision system.
Dostawca treści:: Biblioteka Nauki

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