scholarly journals Application of the DIC Technique to Remote Control of the Hydraulic Load System

2020 ◽  
Vol 12 (21) ◽  
pp. 3667
Author(s):  
Radosław Jasiński ◽  
Krzysztof Stebel ◽  
Jarosław Domin
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Control Method ◽  
Test Stand ◽  
Reinforced Concrete Beams ◽  
Image Correlation ◽  
Optical Measurements ◽  
Electronic Speckle Pattern Interferometry ◽  
Bending Moments ◽  
Test Results

Displacements or deformations of materials or structures are measured with linear variable differential transducers (LVDT), fibre optic sensors, laser sensors, and confocal sensor systems, while strains are measured with electro-resistant tensometers or wire strain gauges. Measurements significantly limited to a point or a small area are the obvious disadvantage of these measurements. Such disadvantages are eliminated by performing measurements with optical techniques, such as digital image correlation (DIC) or electronic speckle pattern interferometry (ESPI). Many devices applied to optical measurements only record test results and do not cooperate with the system that exerts and controls load. This paper describes the procedure for preparing a test stand involving the Digital Image Correlation system ARAMIS 6M for remote-controlled loading. The existing hydraulic power pack (ZWICK-ROELL) was adapted by installing the modern NI cRIO-9022 controller operating under its own software developed within the LABVIEW system. The application of the DIC techniques to directly control load on the real structure is the unquestionable innovation of the described solution. This led to the elimination of errors caused by the test stand susceptibility and more precise relations between load and displacements/strains which have not been possible using the previous solutions. This project is a synergistic and successful combination of civil engineering, computer science, automatic control engineering and electrical engineering that provides a new solution class. The prepared stand was tested using two two-span, statically non-determinable reinforced concrete beams loaded under different conditions (force or displacement). The method of load application was demonstrated to affect the redistribution of bending moments. The conducted tests confirmed the suitability of the applied technique for the remote controlling and recording of test results. Regardless of the load control method (with force or displacement), convergent results were obtained for the redistribution of bending moments. Force-controlled rotation of the beam section over the support was over 50% greater than rotation of the second beam controlled with an increase in the displacement.

scholarly journals Strain and Displacement Measurements in Reinforced Self-Compacting Concrete Beams with Openings Using Digital Image Correlation Technique

Proceedings ◽  
2020 ◽  
Vol 63 (1) ◽  
pp. 39
Author(s):  
Alexandra Coșa ◽  
Bogdan Hegheș ◽  
Camelia Negruțiu ◽  
Zoltan Kiss
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Image Correlation ◽  
Optical Measurements ◽  
Critical Parameters ◽  
Small Scale ◽  
Correlation Technique ◽  
Self Compacting Concrete

In structural engineering, strain and displacement are critical parameters, and measuring these parameters outside of the laboratory is a challenge for concrete researchers. Recent advances have enabled digital image correlation (DIC) to calculate the concrete surface displacements of chosen targets in a series of images recorded during an experiment. This paper presents a comparison between traditional and optical measurements to evaluate the efficiency of the DIC technique in recording the deformations of reinforced concrete beams. Tests were perfomed on two small-scale reinforced self-compacting concrete beams with small circular openings in 3-point bending.

scholarly journals Crack Propagation Analysis of Synthetic vs. Steel vs. Hybrid Fibre-Reinforced Concrete Beams Using Digital Image Correlation Technique

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Aniket B. Bhosale ◽  
S. Suriya Prakash
Keyword(s):  
Reinforced Concrete ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Fracture Behaviour ◽  
Process Zone ◽  
Reinforced Concrete Beams ◽  
Image Correlation ◽  
Correlation Technique ◽  
Fibre Reinforced Concrete ◽  
Hybrid Fibre

Abstract Improvement in fracture behaviour of fibre-reinforced concrete (FRC) due to the inclusion of various types and combinations of fibres is widely reported. The fracture behaviour of FRC needs to be fully understood for the optimum use of these fibres in structural elements. Fracture behaviours of synthetic fibre-reinforced concrete (SynFRC), hybrid fibre-reinforced concrete (HFRC) and steel fibre-reinforced concrete (SFRC) are investigated in this study using digital image correlation (DIC) technique. This work focuses on improvement in the structural performance of FRC through a comprehensive study of the change in the crack length, crack opening and fracture process zone (FPZ) due to different fibres addition and their combinations. Three distinct fibre dosages of 0.50%, 0.75%, and 1.00%, of macro-polyolefin fibres, hooked end steel fibres and their hybrid combination are regarded as research parameters. Test outcomes indicate that HFRC offers higher post-cracking resistance when compared to SynFRC. SFRC showcases superior fracture performance than that of HFRC and SynFRC. Full-field strain measurements from DIC are used to measure the crack openings at different load levels during the fracture tests. Results of DIC analysis show good agreement with experimental measurements. Continuous monitoring of strain contours using DIC reveals the effective engagement of fibres along the depth at higher dosages for HFRC when compared to that of SynFRC. Also, HFRC had longer cracks than SFRC at a particular load.

Digital Image Correlation Based Method of Crack Growth Rate and Fracture Toughness Measurements on Mini-Samples

2013 ◽  
Vol 586 ◽  
pp. 96-99
Author(s):  
Tomasz Brynk ◽  
Anatolii Laptiev ◽  
Oleksandr Tolochyn ◽  
Zbigniew Pakiela
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Optical Measurements ◽  
Displacement Fields ◽  
Strain Measurements ◽  
Special Approach ◽  
Tip Position ◽  
Sintering Method

Modern materials fabrication methods which utilize severe plastic deformation (SPD) do not often allow to obtain enough volume of material to prepare standardized samples for mechanical tests. Therefore, there is a need for mini-samples testing. Mini-samples tests require special approach in terms of precise strain measurements. Accurate strain measurements may be achieved by means of non-contact optical method, namely Digital Image Correlation (DIC). The aim of this work is to present the methodology and results of mini-samples tests in which displacement fields measurements performed by means of DIC and inverse method were utilized for calculation of stress intensity factors and crack tip position tracking. The influence of the subarea of optical measurements for which calculation were performed on the calculations results has been investigated during tests in SPD processed Al alloys and brittle WC-Co sinters produced by means of impact sintering method.

Error Assessment of Blade Deformation Measurements on a Multi-Megawatt Wind Turbine Based on Digital Image Correlation

2015 ◽  
Author(s):  
Jan Winstroth ◽  
Joerg R. Seume
Keyword(s):  
Digital Image Correlation ◽  
Wind Turbine ◽  
Error Estimation ◽  
Digital Image ◽  
Rotor Blades ◽  
Image Correlation ◽  
Optical Measurements ◽  
Full Field ◽  
Out Of Plane ◽  
Plane Bending

Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformation and vibration in wind turbine rotor blades during operation, in high spatial and temporal resolution. Recent field tests on a multi-megawatt wind turbine have demonstrated the vast potential for full scale testing, however little is known about the overall accuracy of DIC measurements on wind turbines. The present work proposes using a virtual 3D wind turbine model for estimating the error associated with the optical measurements. The entire setup is simulated a priori and accurate error estimation becomes possible. The error estimation for a 3.2 MW wind turbine suggests that relative out-of-plane bending of the rotor blades can be measured with an accuracy of ±9.1 mm, relative in-plane bending of the rotor blades can be measured with an accuracy of ±10.2 mm, and relative blade torsion can be measured with an accuracy of ±0.07 deg. This corresponds to a relative error of 0.46% for out-of-plane bending, 1.11% for in-plane bending and 5.46% for blade torsion.

Validation of Aramis Digital Image Correlation System for Tests of Fibre Concrete Based on Waste Aggregate

2018 ◽  
Vol 761 ◽  
pp. 103-110 ◽  
Author(s):  
Jacek Domski ◽  
Jacek Katzer
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Steel Fibre ◽  
Research Programme ◽  
Image Correlation ◽  
Optical Measurements ◽  
Steel Fibre Reinforced Concrete ◽  
The Matrix ◽  
Correlation System ◽  
Flexural Tests

The paper presents a research programme focused on steel fibre reinforced concrete (SFRC) based on waste ceramic aggregate (WCA) prepared from debris. The matrix was reinforced by steel fibre from 0.5% to 1.5% (by volume). Flexural tests were performed using a limit of proportionality (LOP) method and a procedure based on optical measurements with the help of Digital Image Correlation (DIC) System. Residual strengths were calculated and flexural strength classes were assigned. Conclusions concerning both properties of SFRC based on WCA and feasibility of using DIC system for testing SFRC were drawn.

scholarly journals Key aspects of digital image correlation in impact tests of reinforced concrete beams

2019 ◽  
Author(s):  
Morgan Johansson ◽  
Rasmus Rempling ◽  
Gonzalo S. D. de Ulzurrun ◽  
Carlos Zanuy
Keyword(s):  
Reinforced Concrete ◽  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Concrete Beams ◽  
Computational Cost ◽  
Reinforced Concrete Beams ◽  
Image Correlation ◽  
High Speed Photography ◽  
Key Aspects

<p>This paper studies 2-D high speed photography combined with digital image correlation (DIC) applied to experimental research of reinforced concrete beams at moderate loading rates. The aim of the present research is to understand the influence of 2-D DIC set-up parameters in the results. Drop-weight tests have been completed in 1180 × 100 × 100 mm longitudinally reinforced concrete beams. The study has confirmed results sensitivity to image subdivision and mesh properties. While smaller subdivision sizes allow to obtain results nearby boundaries, being more suitable to study local effects, larger sizes enhance computational cost, increase mesh stability and accuracy. A discussion of key aspects of 2-D DIC for measuring different parameters (such as acceleration, displacements, strains and strain-rate) is presented along this paper.</p>

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