Wyniki wyszukiwania - BazTech

1

Application of mixed-nanoparticle coating as a novel simple method in generating speckle pattern to study small fields of view by digital image correlation

Aghdam Milad Zolfipour, Soltani Naser, Nobakhti Hadi

Archive of Mechanical Engineering

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2022

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LXIX, nr 1

45--58

EN

Digital image correlation (DIC) is a powerful full-field displacement measurement technique that has been used in various studies. The first step in the DIC is to create a random speckle pattern, where the spraying method is usually employed. However, creating an optimal pattern and modification in the spraying method is not convenient. Furthermore, the size of speckles which is not so small in spraying method, limits the minimum size of the field of study. In the present research, a convenient novel technique was introduced and investigated to generate a practical kind of speckle pattern with small speckles for evaluating smaller fields of view using nanoparticles. The pattern was created by spreading a mixture of different black and white nanoparticles. To this end, the black graphene oxide particles were mixed with white nanoparticles of titanium oxide, zirconium oxide and silicon to obtain three mixtures. Displacement tests show that the mixture of graphene and titanium provides the best DIC performance. More granularly, graphene and titanium were mixed at three different ratios to find the optimal combination. Subsequently, the accuracy of the new patterning method was analyzed via tensile testing and the results were compared against those of conventional method with various subset sizes.

2

An experimental study of the vibrational characteristics of a diamond circular blade using electronic speckle-pattern interferometry and fem

Tkach Mykhaylo, Halynkin Yurii, Proskurin Arkadii, Zhuk Irina, Kluchnyk Volodymyr, Bobylev Igor

Acta Mechanica et Automatica

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2021

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Vol. 15, no. 1

16--23

EN

The compact installation and technology for determining vibration characteristics by the ESPI method has been created. The experimental determination of the dynamic characteristics of a diamond circular blade with a diameter of 203.4 mm and a thickness of 1.19 mm using real-time electronic speckle interferometry is presented. 15 mode shapes of vibration were detected in the range from 100 to 5000 Hz. The program calculation of the natural frequencies and mode shapes is carried out for three values of the clamping inner diameter (42 mm, 44 mm, 46 mm). The options for calculating a disk with a rim and without a rim are considered. It is shown that the minimum mean squared error of the calculation is achieved for the values of the diameter of the disk 46 mm, 42 mm and 44 mm for the number of nodal circles 0, 1 and 2, respectively. To verify the accuracy of the interferometer, experimental, computational and analytical studies of console steel rod 200 x 22.25 x 3.78 mm in size were carried out.

3

Two-way ANOVA gage R&R working example applied to speckle intensity statistics due to different random vertical surface roughness characteristics using the Fresnel diffraction integral

Cywiak Moisés, Cywiak David, Yáñez Etna

Metrology and Measurement Systems

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2020

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Vol. 27, nr 1

103--117

EN

We present computer simulations of a two-way ANOVA gage R&R study to determine the effects on the average speckle width of intensity patterns caused by scattered light reflected from random rough surfaces with different statistical characteristics. We illustrate how to obtain reliable computer data that properly simulate experimental measurements by means of the Fresnel diffraction integral, which represents an accurate analytical model for calculating the propagation of spatially-limited coherent beams that have been phase-modulated after being reflected by the vertical profiles of the generated surfaces. For our description we use four differently generated vertical profiles and five different vertical randomly generated roughness values.

4

Luminescent powder technique in electronic speckle pattern photography

Kułak J., Suprynowicz K., Pisarek J.

Physics for Economy

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2019

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Vol. 3, No. 1

15-28

EN

For the generation of speckle images, a luminescent powder applied in a small amount to the sample surface and stimulated by UV radiation was used. We obtained fine-grained speckle patterns with very high contrast and small size of spots, The shape of the single speckle, unlike laser method, is circular, which is important for the effectiveness of the used digital image analysis methods. The measurements of displacements and deformations were made by use of digital image registration and its analysis using correlation procedures. The results are presented in the form of bitmaps, tables and graphs. The developed method was tested on flat wood specimens subjected to three-point bending.

PL

Do generacji obrazów plamkowych wykorzystano proszek luminescencyjny naniesiony w niewielkiej ilości na powierzchnię próbki i pobudzany do świecenia promieniowaniem UV. Uzyskano drobnoziarniste struktury plamkowe (speckle pattern) o bardzo wysokim kontraście i małym rozmiarze plamek, których kształt w przeciwieństwie do speckli laserowych jest kołowy, co ma istotne znaczenie dla skuteczności zastosowanych metod cyfrowej analizy obrazu. Pomiaru przemieszczeń i odkształceń dokonano poprzez cyfrową rejestrację obrazu i jego analizę przy użyciu procedur korelacyjnych. Wyniki zostały przedstawione poglądowo w postaci bitmap oraz w sposób bezpośredni w postaci tablic i wykresów. Opracowana metoda badawcza została przetestowana na płaskich próbkach drewnianych poddanych zginaniu trójpunktowemu.

5

Deformation sensing with a multimode POF using speckle correlation processing method

Varyshchuk V., Bobitski Y., Poisel H.

Opto-Electronics Review

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2017

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Vol. 25, No. 1

19--23

EN

A deformation sensing technique with a multimode plastic optical fibre based on intensity speckle patterns’ correlation coefficient measurement has been presented. Influence of the average speckle size on results of deformation measuring has been studied and discussed. The presented sensing technique pro-vides a good linear response to the applied deformation in a relatively wide operation region. It is shown hat the proposed technique is highly sensitive, low-cost and simple to implement in practice.

6

Multimode polymer optical fiber strain gauge based on speckle correlation

Varyshchuk V, Bobitski Y., Poisel H.

International Journal of Microelectronics and Computer Science

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2014

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Vol. 5, nr 3

111--115

EN

In this paper, we proposed an optical ﬁber strain gauge where the fiber elongation originates from a spatial change in a random intensity pattern which is measured through a correlation coefficient of two speckle image. The optical scheme and the operation principle of strain gauge based on multimode polymer optical fiber is investigated. The possibility of measuring of the relative strain by processing of speckle patterns at the exit face of multimode fiber is studied theoretically and experimentally. The algorithm of correlation processing of speckle pattern is developed too. The sensing technique presented in this paper is simple, effective and low-cost solutions to the problem of small strain monitoring. The proposed method can be used to structural health-monitoring of the elements of buildings and industrial objects.