Wyniki wyszukiwania - BazTech

1

Badania deformacji geosiatki poliestrowej wykorzystywanej w inżynierii lądowej

Górszczyk Jarosław, Malicki Konrad

Materiały Budowlane

|

2024

|

nr 3

32--35

PL

Geosyntetyki to materiały powszechnie stosowane w inżynierii lądowej. W artykule przedstawiono zastosowanie bezkontaktowej metody pomiaru deformacji (digital image correlation method – DIC) w badaniach laboratoryjnych geosiatki ortogonalnej. W badaniach zrealizowanych metodą rozciągania wyznaczono rozkład przemieszczeń i odkształceń dla całych powierzchni badanych próbek. Ponadto określono wartości i wektory własne tensora odkształcenia. Zaobserwowano występowanie lokalnej koncentracji dużych wartości odkształceń głównych na powierzchniach badanych próbek. Potwierdzono skuteczność zastosowania metody cyfrowej korelacji obrazu (DIC) w przeprowadzonych analizach deformacji.

EN

Geosynthetics are one of the materials widely used in civil engineering. The article presents the use of a non-contact deformation measurement method (digital image correlation method - DIC) in laboratory test of an orthogonal geogrid. In tests carried out using the tensile method, the distributions of displacements and strains were determined for the entire surface of the tested samples. Moreover, the principal values and principal directions of the strain tensor were determined. The occurrence of local principal strain accumulations on the surface of tested samples was observed. The effectiveness of the use of the digital image correlation (DIC) method in deformation analysis was confirmed.

2

Non-contact method for measuring deformation in testing selected materials used in road construction

Górszczyk Jarosław, Malicki Konrad

Roads and Bridges - Drogi i Mosty

|

2023

|

Vol. 22, no. 4

423--432

EN

High requirements for materials used in road construction make it necessary to use modern methods for assessing the mechanical parameters of these materials. One such method is the Digital Image Correlation (DIC) method. The paper presents the possibilities of using the non-contact DIC method to measure deformation in testing selected mechanical properties of asphalt mixture samples and a composite made of a polymer matrix reinforced with a glass fiber grid (fiber reinforced polymer – FRP). The paper shows deformation analysis of all the observed surfaces of the tested samples. It was found that in terms of static tensile strength, the performance of the FRP tape is similar to the behavior of geogrids used to strengthen road pavement structures. The discussed results of own research and research described in the literature confirmed the usefulness of the DIC method in testing materials used in civil engineering.

PL

Wysokie wymagania stawiane materiałom stosowanym w budownictwie drogowym powodują konieczność stosowania nowoczesnych metod oceny ich parametrów mechanicznych. Jedną z takich metod jest metoda cyfrowej korelacji obrazu (Digital Image Correlation – DIC). W artykule zaprezentowano możliwości wykorzystania bezkontaktowej metody DIC do pomiaru deformacji w badaniach wybranych cech mechanicznych próbek mieszanki mineralno-asfaltowej oraz kompozytu wykonanego z matrycy polimerowej zbrojonej siatką z włókien szklanych – (fiber reinforced polimer – FRP). W pracy pokazano analizy deformacji całych obserwowanych powierzchni badanych próbek. Stwierdzono też, że pod względem wytrzymałości statycznej na rozciąganie praca taśmy FRP jest podobna do zachowania geosiatek stosowanych do wzmacniania konstrukcji nawierzchni drogowych. Omówione wyniki badań własnych oraz badań opisanych w literaturze potwierdziły przydatność metody DIC w badaniach materiałów stosowanych w inżynierii lądowej.

3

Badania betonowych elementów sprężonych zespolonych z nadbetonem

Zając Jakub, Drobiec Łukasz, Grzyb Krzysztof

Przegląd Budowlany

|

2023

|

R. 94, nr 7-8

126--132

PL

W artykule przedstawiono badania rozwarstwienia prefabrykowanych sprężonych belek betonowych. Głównym celem programu badań jest określenie wpływu kształtu zespolenia na zachowanie się belek zespolonych. Zbadano żebrowe prefabrykowane belki sprężone z pełnym zespoleniem, zerwaną adhezją i zerwaną adhezją oraz tarciem. Pomiary z wykorzystaniem technologii cyfrowej korelacji obrazu (DIC) wraz z analizą charakterystyki siła-przemieszczenie wykazały decydujący wpływ długości rozwarstwienia na pracę elementu. Powstawanie lokalnego poślizgu w płaszczyźnie zespolenia związane było z propagacją zarysowań giętnych i ukośnych. Zarysowanie dochodzące do strefy podparcia należy uznać za moment rozwarstwienia elementu zespolonego.

EN

The article presents a study of the interface behavior of precast pre-stressed composite beams. The main objective of the research program is to determine the influence of the interface’s shape on the composite element’s behavior. The rib-shaped precast prestressed beams with full bond, broken adhesion and broken contact were tested. DIC measurements with force-displacement relations analysis showed a crucial impact of cracking length on element performance. The formation of the local slip of the interface was related to the propagation of flexural and shear cracks. The crack reaching the support zone should be considered the moment of debonding of the composite element.

4

Experimental dynamic damage assessment of PUFJ protected brick infilled RC building during successive shake table tests

Kwiecień Arkadiusz, Rakicevic Zoran, Chełmecki Jarosław, Bogdanovic Aleksandra, Tekieli Marcin, Hojdys Łukasz, Gams Matija, Krajewski Piotr, Manojlovski Filip, Soklarovski Antonio, Halici Omer Faruk, Rousakis Theodoros, Vanian Vachan

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 3

art. no. e144940

EN

It is highly important to determine eigenvalues before and after certain extreme events that may cause damage accumulation, such as earthquake, blasts and mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of wider experimental activities, three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach, and they are presented in detail. They are: inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties, and with the different rate and extent of damage accumulation, as well as to local or global measurements. Y et, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable one, depending on the site conditions. The inertance function method presented manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by the damage and repair process. It offers quite a wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in the structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.

5

Effect of the addition of basalt fiber on life-cycle anti-cracking behavior of concrete

Li Yue, Shen Aiqin, Guo Yinchuan

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e92, 2023

EN

To evaluate the cracking resistance of basalt fiber reinforced concrete (BFRC) in different periods, including the curing period and the service period, restrained slab, restrained ring and three-point bending tests were conducted. In this investigation, various fiber lengths (i.e., 6 mm, 12 mm, and 18 mm) and fiber contents (ranging from 0.07% to 0.09%) were used to prepare BFRC. The plastic shrinkage behavior of BFRC was characterized by monitoring evaporation, bleeding, capillary pressure and plastic shrinkage strain, and the mechanism of the effect of the fibers in reducing plastic cracking was subsequently revealed. The restrained shrinkage strain in the steel ring was measured, and the cracking potential index (ΘCR) was assessed for all BFRC specimens. Furthermore, the fracture behavior, including the strain distribution and cracking process, was monitored by the digital image correlation (DIC) technique. The results showed that long basalt fibers (12 mm and 18 mm) effectively delayed the occurrence of the plastic settlement and reduced capillary pressure, resulting in a decreased crack width of concrete. The basalt fibers also led to a pronounced decrease in the ΘCR of the concrete, particularly at an early curing age (3 d). Moreover, the DIC test revealed that the crack occurrence was accompanied by a fuctuation in the strain field during the fracture process. Basalt fibers considerably slowed the formation and evolution of the strain stripes of the concrete under load, and consequently, the fracture energy and cracking resistance capacity of concrete can be improved by the addition of basalt fibers.

6

Deformation behaviour of high-manganese steel with addition of niobium under quasi-static tensile loading

Jabłońska Magdalena Barbara, Jasiak Katarzyna, Kowalczyk Karolina, Bednarczyk Iwona, Skwarski Mateusz, Tkocz Marek, Gronostajski Zbigniew

Materials Science Poland

|

2022

|

Vol. 40, No. 3

1--11

EN

In this paper, the heat generated during deformation under the static testing of high-manganese TWIP steel with addition of niobium was determined. The research combined the interaction of heat generated during deformation, mechanical properties, hardness and microstructure. Temperature and strain were measured simultaneously using infrared (IR) thermography and digital image correlation (DIC) method. The average temperature measured at the necked region equals 42°C at the strain rate of 0.001 s−1 and exceeds 100°C at 0.5 s−1. Therefore at large strains, a reduction in stress was observed. The course of the hardness change coincides very well with the strain changes, however, at the strain rate of 0.5 s−1 near to the necking area the hardness equals to 360 HV2, whereas at the lower strain rates it equals to 370 HV2. These changes are connected mainly with increase in temperature to >100°C

7

Możliwości wykorzystania cyfrowej korelacji obrazu do badań w budownictwie drogowym

Ciołczyk Adrian, Walotek Konrad, Bzówka Joanna

Drogownictwo

|

2022

|

nr 6

173--178

PL

W artykule zaprezentowano przegląd możliwości badawczych w budownictwie drogowym z wykorzystaniem metody cyfrowej korelacji obrazu (DIC). Przedstawiono możliwości przeprowadzania badań laboratoryjnych na próbkach materiałów drogowych, jak i badania polowe na wykonanych nawierzchniach drogowych. Opisano możliwość badania nawierzchni asfaltowych, jak również nawierzchni z płyt granitowych/betonowych.

EN

The paper presents an overview of the possibilities using the digital image correlation (DIC) method in road engineering. The possibilities of conducting laboratory tests for road materials samples as well as field tests performed on road surfaces are presented. The possibilities of testing asphalt surfaces and the surfaces made of granite or concrete slabs are also described.

8

Evaluation of a low-cost approach to 2-D digital image correlation vs. a commercial stereo-DIC system in Brazilian testing of soil specimens

Arza-García M., Núňez-Temes C., Lorenzana J. A., Ortiz-Sanz J., Castro A., Portela-Barral M., Gil-Docampo M., Bastos G.

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 1

art. no. e4, 2022

EN

Due to their cost, high-end commercial 3D-DIC (digital image correlation) systems are still inaccessible for many laboratories or small factories interested in lab testing materials. These professional systems can provide reliable and rapid full-field measurements that are essential in some laboratory tests with high-strain rate events or high dynamic loading. However, in many stress-controlled experiments, such as the Brazilian tensile strength (BTS) test of compacted soils, samples are usually large and fail within a timeframe of several minutes. In those cases, alternative low-cost methods could be successfully used instead of commercial systems. This paper proposes a methodology to apply 2D-DIC techniques using consumer-grade cameras and the open-source image processing software DICe (Sandia National Lab) for monitoring the standardized BTS test. Unlike most previous studies that theoretically estimate systematic errors or use local measures from strain gauges for accuracy assessment, we propose a contrast methodology with independent full-field measures. The displacement fields obtained with the low-cost system are benchmarked with the professional stereo-DIC system Aramis-3D (GOM GmbH) in four BTS experiments using compacted soil specimens. Both approaches proved to be valid tools for obtaining full-field measurements and showing the sequence of crack initiation, propagation and termination in the BTS, constituting reliable alternatives to traditional strain gauges. Mean deviations obtained between the low-cost 2D-DIC approach and Aramis-3D in measuring in-plane components were 0.08 mm in the perpendicular direction of loading (ΔX) and 0.06 mm in the loading direction (ΔY). The proposed low-cost approach implies considerable savings compared to commercial systems.

9

Experimental and computational approaches to the evaluation of double corrugated arch structures. A review of the latest advancements

Piekarczuk Artur, Więch Przemysław, Kuczyński Krzysztof, Walentyński Ryszard

Archives of Civil Engineering

|

2021

|

Vol. 67, nr 2

7--35

EN

Double corrugated, self-supporting K-span arch structures are now commonly used globally to make roofs for building structures, as an alternative to traditional solutions. The K-span system has become popular mainly due to the simple and cheap method of its manufacturing and quick installation. Nowadays, new versions of the system are created but still there is no valid design method. Design difficulties are among the causes of failures or even collapses of such structures. Back in the 1970s, the first studies were developed concerning computational analyses of double corrugated arch roofs. They laid grounds for the development of contemporary K-span system technology but have since lost their practical advantages due to changing engineering conditions. The paper presents a review of research and computational methods concerning double corrugated arch structures. The paper discusses selected scientific studies, which were used as the basis for the development of research and computational methods, and their contemporary continuation. Directions for further research and analyses are also presented which could contribute to the future development of science and engineering in the area and could provide inspiration for future studies.

PL

Podwójnie gięte, samonośne struktury łukowe systemu K-span, stosowane są obecnie na runku światowym do wykonywania zadaszeń obiektów budowlanych jako alternatywna technologia w odniesieniu do tradycyjnych rozwiązań. System konstrukcyjny K-span zyskał popularność głównie z powodu prostej i taniej metody wytwarzania oraz szybkiego montażu. Obecnie powstają nowe odmiany tego sytemu, jednak nadal brak jest odpowiedniego sposobu projektowania. Trudności w projektowaniu są jedną z przyczyn awarii a nawet katastrof tego typu struktur. W latach osiemdziesiątych ubiegłego stulecia powstały pierwsze opracowania studialne dotyczące analiz badawczych i obliczeniowych zadaszeń łukowych z blach podwójnie giętych. Stanowiły one podstawy rozwoju dzisiejszej technologii systemu K-span, jednak straciły walory praktyczne z uwagi na zmieniające się uwarunkowania techniczne. Artykuł stanowi przegląd rozwoju technik badawczych i obliczeniowych dotyczących struktur łukowych z blach podwójnie giętych. W artykule przedstawiono wybrane prace naukowe, które były podstawą rozwoju technik badawczych i metod obliczeniowych a także ich współczesną kontynuację.

10

Investigation of the correlation between crack propagation process and the peak strength for the specimen containing a single pre-existing flaw made of rock-like material

Yang Hengtao, Lin Hang, Wang Yixian, Cao Rihong, Li Jiangteng, Zhao Yanlin

Archives of Civil and Mechanical Engineering

|

2021

|

Vol. 21, no. 2

458--478

EN

This paper investigated the relationship between the strength of fractured rock and the crack propagation process. A series of uniaxial compression tests were carried out on the rock-like material specimens with single pre-fabricated flaw. Moreover, DIC (digital image correlation) technology was utilized to monitor and analyze the failure process of specimens. The initiation of each crack was defined as a key event, and the relationship between several key events and the axial load of the specimen during the crack propagation was quantitatively analyzed. The time-sequence analysis of crack propagation was also conducted by selecting benchmark points on the both sides of major cracks. It can be found that only the wing crack propagation occurs and there is no obvious shear crack before the peak strength. When the first secondary crack initiated, the specimen reached its peak strength and the wing crack just reached its critical length. Beyond the peak strength, secondary cracks initiated and coalesced rapidly, which leads to the sudden failure of fractured rock. Therefore, the peak strength of the specimen can be assessed by taking the critical length of the steadily propagating wing crack as the condition which determines whether the specimen reaches the peak strength. Furthermore, the discrete element numerical simulation was also implemented to confirm the experimental results.

11

An Influence of Geometrical Parameters of the Lock of the Blade-Disc Joint on Stress in the FEA and DIC Methods

Kozakiewicz Adam, Grzejszczak Olga

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no 1

209--217

EN

In this paper, an assessment of strength properties of the existing blade-disc dovetail joint was presented, taking the parametric optimization of its geometry. A sensitivity of the analysis was carried out to determine the relationship between the selected geometric parameters and strength properties of the structure questioned. The results from experiments and computer simulations were compared. In addition, the fatigue life of the structure was analyzed for different materials and using the change of speed ranges and parameterization of geometry.

12

Walidacja korzystnej ilości popiołu lotnego w betonie z uwagi na odporność na pękanie za pomocą metody cyfrowej korelacji obrazu

Golewski Grzegorz Ludwik

Materiały Budowlane

|

2020

|

nr 10

36--39

PL

W artykule skoncentrowano się na analizie procesów pękania w betonie z popiołem lotnym (fly ash – FA) z uwzględnieniem drugiego modelu pękania i określono parametr KIIc. Głównym celem badań było potwierdzenie zbieżności i określenie zakresu rozbieżności pomiędzy wynikami KIIc uzyskanymi na prasie MTS 810 i z zastosowaniem cyfrowej korelacji obrazu (Digital Image Correlation – DIC). Analiza wyników badań wykazała wyraźną zbieżność między wartościami uzyskanymi z obu urządzeń pomiarowych. Ponadto wyniki badań potwierdzają zależności z wcześniejszych doświadczeń dotyczących odporności na pękanie betonu zawierającego FA, przeprowadzonych przy pierwszym modelu pękania.

EN

The article focuses on analyzing the fracture processes in fly ash (FA) concrete taking into account the second model of cracking and the KIIc parameter was determined. Two measuring devices were used in the studies. The main goal of the studies was to confirm the convergence and determine the discrepancy ranges, between the KIIc results obtained on the MTS 810 press and the use of the Digital Image Correlation (DIC). The analysis of the obtained test results showed clear convergences between the values obtained from both measuring devices. Furthermore, the presented test results also confirm the values of previous experiments on fracture toughness of concrete containing FA conducted at the first model of cracking.

13

Modular Test Stand for Fatigue Testing of Aeronautical Structures - Verification of Assumptions

Leski Andrzej, Wronicz Wojciech, Kowalczyk Piotr, Szmidt Michał, Klewicki Robert, Włodarczyk Karol, Uliński Grzegorz

Fatigue of Aircraft Structures

|

2020

|

Iss. 12

78--91

EN

The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object. Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment. The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.

14

Analysis of precast lintels behaviour in walls confined by reinforced lightweight and ordinary concrete

Mazur Wojciech, Rybarczyk Tomasz

Budownictwo i Architektura

|

2020

|

Vol. 19, no 3

92--102

EN

This paper presents the test results of reinforced precast lintels made of autoclaved aerated concrete (AAC) used to cover window openings in walls made of AAC masonry units. Walls were confined with reinforced lightweight concrete. The two variants of wall confinement with different way of lintel support and the static diagram of a simply supported beam and a constrained beam were tested. Cracks and deformations of test models around window openings were recorded with the Aramis software for non-contact measurements of displacements. Failure of lintels caused the loss of load capacity of test models. Lintels were cracked in the same way, but the sequence of crack formation and their location were different. The test results were compared with the test made for similar walls confined with ordinary concrete. Additional tie-columns did not significantly affected the load capacity of the test models contrary to the walls confined with ordinary concrete.

PL

W artykule przedstawiono wyniki badań ścian skrępowanych zbrojonym betonem lekkim wykonanych z elementów murowych z autoklawizowanego betonu komórkowego (ABK). Do przykrycia otworów okiennych zastosowano prefabrykowane zbrojone nadproża z ABK. Ściany skrępowano w dwóch wariantach zmieniając także sposób oparcia nadproży i schemat statyczny, belki swobodnie podpartej oraz belki utwierdzonej. Za pomocą systemu Aramis do bezdotykowego pomiaru przemieszczeń rejestrowano zarysowania oraz odkształcenia obszarów modeli badawczych wokół otworu okiennego. Zniszczenie nadproży spowodowało utratę nośności modeli badawczych Nadproża uległy zarysowaniu w analogiczny sposób, jednakże zmieniała się kolejność i lokalizacja poszczególnych rys. Wyniki badań porównano z wynikami uzyskanymi dla analogicznych ścian skrępowanych betonem zwykłym. Dodatkowe rdzenie żelbetowe nie wpłynęły w tak istotny sposób na nośność modeli badawczych jak to miało miejsce w przypadku ścina skrępowanych betonem zwykłym.

15

Zmiana odkształceń ścian z elementów murowych z ABK spowodowana oddziaływaniem żelbetowych elementów krępujących

Drobiec Łukasz, Jasiński Radosław, Rybarczyk Tomasz, Cygan Grzegorz, Mazur Wojciech

Materiały Budowlane

|

2019

|

nr 12

30--33

PL

W artykule przedstawiono wyniki pomiarów odkształceń ścian z elementów murowych z ABK w trakcie wykonywania żelbetowego skrępowania. Ściany w skali naturalnej o grubości 180 mm wzniesiono z bloczków nominalnej klasy gęstości 600, na systemowej zaprawie cienkowarstwowej, bez wypełniania zaprawą spoin czołowych. W trakcie procesu krępowania monitorowano odkształcenia ścian. Badania wykazały wpływ rodzaju zastosowanego betonu na przebieg procesu skurczu betonu oraz wartości odkształceń ścian.

EN

The article presents the results of measurements of AAC wall deformations during the process of their restraint with reinforced concrete cores and beam. Full scale walls thickness of 180 mm were made of 600 nominal density class blocks on a system thin-layer mortar, without filling the perpend joints. During the restraining process, wall deformations were monitored. Studies have shown the impact of the type of concrete used on the concrete shrinkage process and the wall strains.

16

Analiza zachowania prefabrykowanych nadproży z ABK w ścianach skrępowanych

Mazur Wojciech

Materiały Budowlane

|

2019

|

nr 8

53--55

PL

W artykule przedstawiono wyniki badań zbrojonych prefabrykowanych nadproży z autoklawizowanego betonu komórkowego (ABK), obciążonych wraz z murem. Modele ścian wykonano w skali naturalnej w trzech wariantach: ściany nieskrępowanej; skrępowanej po obwodzie oraz skrępowanej obwodowo z dodatkowymi rdzeniami wzdłuż pionowych krawędzi otworu okiennego. Analizowano wpływ skrępowania na przebieg zarysowania i zniszczenia nadproży. Badania monitorowano za pomocą systemu Aramis do bezdotykowego pomiaru przemieszczeń (Cyfrowej Korelacji Obrazu - CKO), a wyniki analizowano za pomocą oprogramowania GOM Correlate.

EN

The paper presents results of experimental tests of reinforced precast lintels made of autoclaved aerated concrete (AAC) loaded with masonry wall. Three types of wall made in natural scale erected as: no confined wall, confined wall and confined wall with additional vertical reinforced concrete confining cores along vertical edges of window opening. Cracks’ propagation and destruction of lintels was analyzed. The tests were monitored by Aramis system for non-contact displacement measurement (Digital Image Correlation) and results were analyzed by GOM Correlate software.

17

Metoda DIC

Marcinczak Dorota

Builder

|

2019

|

R.23, nr 2

66--68

EN

The article presents tests of a reinforced concrete beam strengthened in a shear with PBO-FRCM composite materials. Measurement of the deformation of the composite was carried out using two methods - with strain gauges and the optical DIC method (Digital Image Correlation). The DIC method consists in taking a series of photographs of the tested object before and during loading. The surface of the tested element must have randomly spaced spots that are applied to the object before measurement. During the study, the cameras monitor the shifting of spots against each other, which in comparison to the reference image before loading gives information about strains and stresses of the tested element. Measurements of deformation of composite materials using strain gauges are difficult to clearly analyze, because the strain gauge is in a specific, limited place, which does not correspond to the work of the entire composite. In addition, the strain gauge tends to break at the place of crack. The article discusses this problem by presenting the results of deformation of PBO-FRCM composite meshes measured in two mentioned ways, their comparison and discussion of results.

18

Digital image correlation systems in the experimental investigations: capabilities and limitations

Krawczyk Ł., Gołdyn Michał, Urban Tadeusz

Archives of Civil Engineering

|

2019

|

Vol. 65, nr 1

171--180

EN

The aim of the paper is to present the possibilities and limitations of using the Digital Image Correlation systems. In order to assess the measurement inaccuracies the measuring volume 1250 × 1100 mm was analysed using two cameras with sensor resolution 6 megapixels. It was stated very good accuracy of the line segment length change. It causes that observation of crack widths can be considered as precisely. Some practical information concern how determine the compatibility between crack width measured traditionally and by using DIC are given. In the second part of the paper the results of the tests concerning capacity of interface between two concrete casting at the same time were presented. Use of the optical measurement system Aramis enables the analysis of the deformation, determination of failure mode of the tested specimens and limit displacement between edges of the interface.

PL

Celem artykułu jest przedstawienie możliwości i ograniczeń stosowania systemów cyfrowej korelacji obrazu (CKO). W celu oceny niedokładności pomiaru przeanalizowano pole pomiarowe o wymiarach 1250 x 1100 mm, wykorzystując dwa aparaty o rozdzielczości matryc 6 megapikseli. Stwierdzono bardzo dobrą dokladność wyznaczenia zmiany długości odcinka. Dzięki temu obserwację szerokości rys można uważać za dokładną. W artykule zawarto praktyczne informacje dotyczące tego, w jaki sposób prowadzić pomiar szerokości rozwarcia rys za pomocą CKO. W drugiej części artykułu przedstawiono wyniki badań dotyczących nośności styku elementów betonowanych w tym samym czasie. Zastosowanie optycznego układu pomiarowego Aramis umożliwiło analizę odkształcenia, określenie sposobu zniszczenia badanych próbek i granicznych przemieszczeń między krawędziami połączenia.

19

Zastosowanie systemu cyfrowej korelacji obrazu do badań krytycznego rozwarcia wierzchołka szczeliny w betonie zawierającym popiół lotny

Golewski G. L.

Materiały Budowlane

|

2018

|

nr 12

82--85

PL

W artykule przedstawiono wyniki badań odporności na pękanie betonów z dodatkiem popiołów lotnych (Fly ash – FA), których celem było określenie wpływu dodatku FA na wartość nieliniowego parametru mechaniki pękania, tj. krytycznego rozwarcia wierzchołka szczeliny (CTODc). Badania przeprowadzono z wykorzystaniem dwóch urządzeń pomiarowych, tzn. prasy MTS 810 i systemu cyfrowej korelacji obrazu (DIC) z oprogramowaniem ARAMIS. Wartości parametrów mechaniki pękania obliczone na podstawie danych z systemu ARAMIS określają zachowanie się materiału konstrukcyjnego bezpośrednio w momencie inicjacji rysy pierwotnej. Przedstawione wyniki badań wskazują na przydatność metody DIC w tego typu eksperymentach, natomiast artykuł potwierdził duży potencjał techniki DIC w oznaczaniu odporności na kruche pękanie w betonie z dodatkiem FA.

EN

This paper presents results of fracture toughness tests of concrete modified with the addition of fly ash (FA). A nonlinear fracture mechanics parameter were analyzed in this studies, i.e. the critical crack tip opening displacement (CTODc). This factor were determined based on the results obtained from the MTS 810 press and the Digital Image Correlation system (DIC) with ARAMIS software. Based on the studies it was found that, the values of CTODc calculated on the basis of data from the ARAMIS system show the behaviour of the structural material directly at the moment of initiation of the initial crack. The presented research results show the usefulness of the DIC method in this type of experiments, whereas the article confirmed the high potential of DIC technique in determinations fracture toughness in concrete with FA additives.

20

Investigations of material behaviour under monotonic tension using a Digital Image Correlation system

Szymczak T.

Journal of Theoretical and Applied Mechanics

|

2018

|

Vol. 56 nr 3

857—871

EN

The paper reports behaviour of engineering materials for different kinds of notches, i.e. having U, V shapes. Their variants with respect to dimensions are illustrated in static and fatigue tests. The influence of these types of geometrical imperfections on material fatigue is presented using variations of the Wöhler curve, number of cycles to failure and the fatigue notch factor. Results of experiments conducted by the use of the Digital Image Correlation system called 4M Aramis are illustrated. Courses of tensile characteristics of the 41Cr4 steel, obtained by means of both techniques: extensometer and DIC are compared. They indicated that the DIC technique can be a good tool for determination of mechanical properties. The equivalent strain full-field distributions on specimens tensioned with and without imperfections up to material fracture are presented. The influence of U and V notches on variations of tensile curves is shown.