Wyniki wyszukiwania - BazTech

1

Impact of the interface on the fatigue life of steel-based explosively welded heterostructured plates

Derda Szymon, Korolczuk Aleksander, Robak Grzegorz, Prażmowski Mariusz, Paul Henryk, Łagoda Tadeusz, Gupta Munish Kumar

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e191, 2023

EN

Melted zones, microcracks, shear bands, and elastic incompatibility of explosively welded materials are features that may initialize cracks at the interface and reduce fatigue strength. This study aims to determine the effect of interfacial defect-like structures on the fatigue strength of explosively welded corrosion-resistant plates. Cyclic axial loading was applied to seven distinct layer-by-layer compositions of Ti Gr 1, Zr 700 alloys, and carbon steels. The interfacial wave height as a metric of potential fatigue life influencing factors along with measured strain amplitude was applied as the input quantities for the Machine Learning based model, i.e. the Gaussian process for regression (GPR). This is a novel and successful application of GPR to estimate the effect of interfacial wave height on the fatigue life of explosively welded plates. For the first time, the effect of the interface feature on fatigue life was estimated quantitatively. The Digital Image Correlation technique was applied to measure the field of cyclic strain for the purpose of verifying if a single strain amplitude is representative of a heterostructured plate. It was found that interfacial wave height is an important feature and its increase by 100 µm reduces the fatigue life of analysed plates by 36%. Additionally, to validate the applicability of explosively welded plates to engineering structures under cyclic loading, the experimental fatigue lives were compared with the design curve of the American Society of Mechanical Engineers (ASME) code.

2

Digital Image Correlation Method in Monitoring Deformation During Geogrid Testing

Górszczyk Jarosław, Malicki Konrad

Fibres & Textiles in Eastern Europe

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2019

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Vol. 27, no. 2 (134)

84--90

EN

This article presents the results of tests on geogrids conducted using the Digital Image Correlation (DIC) method and those of numerical simulations of laboratory tests on the geogrid using the wide-width strip method. DIC allowed for the non-contact determination of displacements and strains for the entire surface of the samples of geosynthetics tested. The results of the laboratory tests and numerical simulations have been compared. The results of the tests and analyses indicate that the DIC method is an effective tool for evaluating the parameters of geogrids used in GRS systems and in pavement structures. In addition to the standard deformation image for the averaged base, analysis of deformations in any direction and at any point on the surface of the geogrid is possible. The measurement method applied also opens possibilities for validation of numerical models of geogrids made using the finite element method (FEM).

PL

W artykule zaprezentowano wyniki laboratoryjnych badań geosyntetyków przeprowadzonych z wykorzystaniem metody cyfrowej korelacji obrazu (Digital Image Correlation) oraz ich porównanie z wynikami uzyskanymi tradycyjną tensometryczną metodą pomiarową. Badaniom wytrzymałościowym metodą szerokich próbek poddano geosiatki poliestrowe i szklane. W artykule zaprezentowano również numeryczny model przeprowadzonego badania. Wyniki symulacji numerycznych odniesiono do wyników badań laboratoryjnych. Zrealizowane badania materiałów geosyntetycznych oraz analizy uzyskanych wyników pozwoliły na sformułowanie szeregu wniosków. Pierwszym spostrzeżeniem było, iż dwuwymiarowa analiza deformacji metodą DIC pozwala na bezkontaktowe określenie całościowego charakteru pracy powierzchni badanego geosyntetyku. Daje to możliwość określenia rejonów najbardziej wytężonych, również poza obszarem bazy. Kolejną ważną zaletą metody jest możliwość analizy zagadnienia wartości i wektorów własnych wraz z wyznaczeniem pól przemieszczeń i odkształceń dla całej powierzchni badanej próbki. Rozwiązanie to nie jest możliwe przy wykorzystaniu tradycyjnej tensometrycznej metody pomiarowej. Istotne jest również otwarcie możliwość walidacji modeli numerycznych wykonanych przy użyciu metody elementów skończonych.

3

The experimental study of glass multilayer columns using digital image correlation

Demchyna B., Surmai M., Tkach R.

Archives of Materials Science and Engineering

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2019

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Vol. 96, nr 1

32--41

EN

Purpose: The purpose of the research is to study the deformability of glass multilayer columns at the central compression using digital image correlation. It becomes possible to use the method of digital image correlation for the experimental study of load bearing building structures of glass. Design/methodology/approach: The approach which has been used to solve the above problems is to conduct an experimental study of glass columns on central compression, in which deformations were measured using digital image correlation. Findings: The possibility of using load bearing building structures of glass triplex has been discovered. A program of experimental studies was developed. It included the testing of prototype samples on central compression with rigid fastening. On the basis of the obtained results, a graph of dependence of relative deformations on normal tension, graphs of the dependence of the bending of columns on load in different planes, and a modulus of elasticity of triplex glass have been determined. Research limitations/implications: The lack of a calculation methodology and regulatory documents for designing load bearing building structures of triplex glass increases their cost, since each project is individual and requires the experimental research. Practical implications: Using the approaches developed in the paper, the method of digital image correlation, which is to measure deformations when testing glass structures on central compression can be applied. Originality/value: The experimental study is probably the first one in which deformations of glass columns are determined using the method of digital image correlation, so it is new and original. The lack of a calculation methodology and regulatory documents for designing load bearing building structures of triplex glass, increases their cost, since each project is individual and requires the experimental research.

4

Digital image correlation (DIC) on fresh cement mortar to quantify settlement and shrinkage

Dzaye Evin Dildar, Tsangouri Eleni, Spiessens Karel, de Schutter Geert, Aggelis Dimitrios G.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

205--214

EN

The displacement of fresh cementitious media initiated by water evaporation and cement hydration is very complex. In the plastic state, the cement particles deform in the plane and move at different rates leading to the development of plastic shrinkage cracks. In parallel, the material settles as bleed water is released. Tracking the particles three-dimensional heterogeneous displacement requires a highly-sensitive monitoring technique. Digital image correlation (DIC) has been selected to quantify settlement and shrinkage strain evolution. DIC excels compared to classical LVDT point-transducers since it is non-contact and the analysis is full field providing a three-dimensional (3D) view of deformations and strains. 3D visualization maps of early-age deformation contribute to the interpretation of early age mobility. DIC enables the measurement of non-uniform surface displacement due to material heterogeneity and geometry that affects the shrinkage distribution which cannot be detected by traditional LVDTs. The procedure through which the DIC speckle pattern is applied on a wet rough surface is critically discussed.

5

Combining digital image correlation and probabilistic approaches for the reliability analysis of composite pressure vessels

Garcia-Martin Roberto, Bautista-de Castro Álvaro, Sánchez-Aparicio Luis Javier, Fueyo José G., Gonzalez-Aguilera Diego

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

224--239

EN

The accuracy of reliability analysis of composite solutions depends on the robust estimation of the uncertainties associated with the mechanical properties of this material. On this basis, we propose a methodology able to exploit the full field strain data provided by the digital image correlation approach in order to extract the probabilistic density functions of the mechanical properties. These probabilistic density functions are complemented by a global sensitivity analysis based on the polynomial chaos expansion and a random variable approach, based on the latin hypercube sampling method, with the aim of obtaining a stochastic evaluation of composite pressure vessels.

6

Digital Image Correlation and nanoindentation in evaluation of material parameters of cancellous bone microstructure

Kokot G., Skalski K., Makuch A., Ogierman W.

Archives of Materials Science and Engineering

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2017

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Vol. 83, nr 1

10--16

EN

Purpose: Purpose of this paper is to present the possibilities of the application of the two methods: Digital Image Correlation and nanoindentation in porous bone tissues testing. Firstly, as a tool in the evaluation process of material parameters for porous microstructures, such as bone tissues or other foams and, secondly, as validation and verification tools for finite element analysis of bone or foams structures. Those methods are helpful when the high accuracy of the mechanical parameters of porous microstructures is required. Design/methodology/approach: Two methods: Digital Image Correlation (DIC) and nanoindentation are used as an efficient approach in the evaluation process of material parameters or constitutive relationship of porous structures like bone tissues. Digital image correlation enlarges the accuracy of classical mechanical tests and the nanoindentation allows to look inside the microstructure. Findings: The proposed methods were found to be effective in experimental testing and material parameters evaluation process of some special materials. Among them are porous structures, such as bone tissue. Additionally, the DIC is an excellent tool for finite element model validation and results verification. Practical implications: The presented method based on the combination of the Digital Image Correlation and nanoindentation presents new possibilities in material testing fields, material behavior and parameters evaluation. They have great advantages, among others, in the field of testing of porous bone structure or determining the mechanical parameters of bone tissue. Originality/value: The paper presents methods for testing the complicated porous bone structures: evaluating mechanical behavior of the whole structure and evaluating mechanical properties of the single element of the structure. The mechanical parameters of human cancellous bone structures are presented as the preliminary research results.

7

Application of 3D DIC Displacement Field Measurement in Residual Stress Calculations

Brynk T.

Advances in Materials Science

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2017

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Vol. 17, nr 3(53)

46--53

EN

The knowledge of residual stress distribution is of great importance from the viewpoint of both, industrial and basal research. The most commonly utilized method of residual stress determination is based on strain measurements near the drilled holes of known geometry made by means of tensometric rosettes. An alternative to tensometers way of strain measurement is Digital Image Correlation (DIC). This optical method utilizes digital images registered during observed object deformation and delivers results in the form of displacement field maps consisting of hundreds or thousands of data points. Therefore, it is possible to deliver much more data in comparison to rosettes (only 3 or 6 tensometers, usually) and use them in the inverse method numeric procedure for residual stress calculations. In the paper the experimental stand consisting of micro driller and stereo imaging system for 3D DIC measurement and its application to residual stress estimation in prestrained steel samples are presented followed by obtained results discussion.

8

Selected Problems of Determining Critical Loads in Sructures with Stable Post–Critical Behaviour

Czapski P., Kubiak T.

Mechanics and Mechanical Engineering

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2016

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Vol. 20, nr 2

79--95

EN

This paper presents selected cases of inapplicability of theory based methods of determining critical loads in thin – walled, composite tubes. 8th layered composite tubes with square cross-section were being subjected to static compression and in order to register experimental data two measuring equipment were employed: strain-gauges and Digital Image Correlation system ARAMIS R. When measurement data were collected five different theory based methods were applied in order to determine critical loads. Cases where it was impossible to apply certain methods or some doubts about correctness of the results occurred were presented and analyzed. Moreover in cases where it was possible, the theory was equivalently transformed, in such a way to fit experimental data and calculate the critical loads.

9

Strain Monitoring in Woven Fabrics with Locally Induced Mass Irregularities Using an Image Based Method

Baghernezhad S., Ghane M., Moezzi M.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 2 (116)

73--80

EN

The aim of this work was to study the effect of induced mass irregularities of yarn on the strain monitoring of fabric during a tensile test. Slub yarns with different induced mass irregularities were produced and used as weft yarns in plain woven fabric. The Digital Image Correlation (DIC) method was used to evaluate the strain distribution map of the fabric during the tensile test. Images of the reference sample as well as of the strained fabric under the sequential strain applied were captured. By applying the DIC method, a strain distribution map of the fabric at a certain value of the strain applied was calculated for all samples. Results of the strain map calculated were then compared with the image of the actual fabric. It was found that there was good agreement between the map of strain distribution calculated by DIC and the local concentration of strain in the fabric. The results also revealed that the variation in strain distribution in the fabric during the tensile test was correlated exponentially to the breaking stress in cN/tex) of yarn as well as the breaking strength in N of the fabric.

PL

Celem pracy było badanie efektu prowadzonych nierównomierności masy liniowej przędzy na badanie odkształcenia tkanin podczas testów wytrzymałościowych. W wątku zastosowano przędze fantazyjne pęczkowe o różnym rozkładzie masy liniowej dla wyprodukowania tkanin o splocie płóciennym. Zastosowano metodę cyfrowej korelacji obrazu dla oceny rozkładu odkształceń. Wykonano mapy rozkładu odkształceń podczas testów wytrzymałościowych. Mierzono i porównywano obrazy próbek wzorcowych. Stwierdzono dobrą zgodność pomiędzy mapami rozkładu odkształceń obliczonymi teoretycznie i potwierdzonymi eksperymentalnie. Zmiany w rozkładzie odkształceń w tkaninie podczas testów wytrzymałościowych wykazały, że istnieje zależność wykładnicza pomiędzy odkształceniami a naprężeniami zrywającymi w cN/tex, oraz siłą zrywającą w N.

10

Influence of different random pattern creation forms on the results of experimental modal analysis performed by high-speed digital image correlation

Hagra M., Schrötter M., Lengvarsky P.

Acta Mechanica et Automatica

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2014

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Vol. 8, no. 1

22--26

EN

In this contribution an influence of random contrast patterns creation on the quality of the obtained results of experimental modal analysis performed by high-speed digital image correlation is described. Three common forms of random pattern creation were investigat-ed. While the first form was presented by the black speckles printed on white matt vinyl foil and bonded on the sample surface, in the sec-ond and the third case, respectively, the black speckles were sprayed on white sprayed sample surface or on paint white one. For the pur-poses of modal parameters estimation in the form of natural frequencies, mode shapes and damping ratios the program called Modan3D, developed in the authors department, was used. The results obtained by Modan3D were compared with the results achieved by system Pulse specialized for vibration analysis.

11

Post–Buckling State of Rectangular Plate Stiffened by Denselly Arranged Ribs. Numerical Analysis and Experimental Investigation

Kopecki H., Święch Ł.

Mechanics and Mechanical Engineering

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2013

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Vol. 17, nr 1

71--87

EN

The paper presents results of comparative experimental examinations and numerical analyses of rectangular plates subjected to shear treated as a skin of half–monocoque aircraft structure. There were considered: the plate without stiffeners 2 mm thick and structure with 1 mm thickness, stiffened by 15 integral ribs. Results of nonlinear numerical FEM analyses and experimental investigations with use of 3D DIC method were compared to ones conducted for smooth plate with equivalent mass. It was documented that introduction of sub–stiffening significant influence on both the form of deformation and distribution of stress in the structure. For smooth plate low cycle fatigue test was conducted.

12

Comparison between direct and indirect measurement methods for bulge tests

Marinho E., Silva-Jr A., Batalha G.

Archives of Materials Science and Engineering

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2013

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Vol. 61, nr 2

77--86

EN

Purpose: To reinforce the standardization of the bulge test measuring procedures by comparison of two different bulge forming measurement methods. Design/methodology/approach: Two different bulge forming measurement methods are used simultaneously in order to reinforce the standardization of the bulge test measuring procedures. An indirect method, Digital Image Correlation (DIC), is compared with a direct one, ultrasound pulse-echo method. Findings: The main conclusion is that the DIC system is a valid indirect measurement method to study bi-axial sheet metal forming. Research limitations/implications: The constant pressure bulge test method was used and it yielded positive results for comparing the direct and indirect method (considering thickness measurement of the bulge dome), as an important research implication is that the touch less measurement method could be applied to other sheet metal forming processes. Practical implications: Tension tests are used as a standard accepted procedure to determine material parameter values for characterizing the forming sheet behaviour. However, by using a tension test, only a limited strain range can be considered for determining the true stress – true strain curve. Based on this limitation, the bulge test is used to achieve a much larger strain range under bi-axial loading conditions. Originality/value: An indirect method, Digital Image Correlation (DIC), is compared with a direct one, ultrasound pulse-echo method, in situ, real time and on the same specimen.