scholarly journals Digital Image Correlation for Cement-based Materials and Structural Concrete Testing

2020 ◽  
Vol 22 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Asdam Tambusay ◽  
Benny Suryanto ◽  
Priyo Suprobo
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Low Cost ◽  
Digital Camera ◽  
Cement Composite ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Image Recording ◽  
Composite Testing

This paper presents the application of a low-cost digital image correlation (DIC) system for automated crack mapping. The system employed makes use of a conventional digital camera, a remote image recording controller, and an open-source digital image correlation MATLAB software Ncorr. To showcase the potential of the proposed system, two case studies involving general structural and material testing were undertaken. In the first series, the DIC system was used to study the fracture processes in a reinforced concrete beam and to investigate the influence of key input parameters on the spatial quality of strain maps obtained from the DIC analysis. In the second series, the application of the DIC method was expanded to assist in the study of complex multiple micro-crack formations in ductile cement composite testing. It is shown that the strain maps obtained from the DIC technique have a close resemblance to the actual crack patterns

scholarly journals New Four Points Initialization for Digital Image Correlation in Metal-Sheet Strain Measurements

2019 ◽  
Vol 9 (8) ◽  
pp. 1691 ◽  
Author(s):  
Alejandro-Israel Barranco-Gutiérrez ◽  
José-Alfredo Padilla-Medina ◽  
Francisco J. Perez-Pinal ◽  
Juan Prado-Olivares ◽  
Saúl Martínez-Díaz ◽  
...  
Keyword(s):  
Image Registration ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Surface Deformation ◽  
Initial Conditions ◽  
Low Cost ◽  
Digital Camera ◽  
Image Correlation ◽  
Camera System ◽  
Metal Sheets

Nowadays, the deformation measurement in metal sheets is important for industries such as the automotive and aerospace industries during its mechanical stamping processes. In this sense, Digital Image Correlation (DIC) has become the most relevant measurement technique in the field of experimental mechanics. This is mainly due to its versatility and low-cost compared with other techniques. However, traditionally, DIC global image registration implemented in software, such as MATLAB 2018, did not find the complete perspective transformation needed successfully and with high precision, because those algorithms use an image registration of the type “afine” or “similarity”, based on a 2D information. Therefore, in this paper, a DIC initialization method is presented to estimate the surface deformation of metal sheets used in the bodywork automotive industry. The method starts with the 3D points reconstruction from a stereoscopic digital camera system. Due to the problem complexity, it is first proposed that the user indicates four points, belonging to reference marks of a “Circle grid”. Following this, an automatic search is performed among the nearby marks, as far as one desires to reconstruct it. After this, the local DIC is used to verify that those are the correct marks. The results show reliability by reason of the high coincidence of marks in experimental cases. We also consider that the quality of mark stamping, lighting, and the initial conditions also contribute to trustworthy effects.

scholarly journals DIC (Digital Image Correlation) method in the research of RC beams strengthened with PBO-FRCM materials

2019 ◽  
Vol 97 ◽  
pp. 03008 ◽  
Author(s):  
Dorota Marcinczak ◽  
Tomasz Trapko
Keyword(s):  
Composite Materials ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Concrete Beam ◽  
Correlation Method ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Strain Gauges ◽  
Reference Image

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 analyse, 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.

Study of the quality of wood texture patterns in digital image correlation

Optik ◽  
2018 ◽  
Vol 171 ◽  
pp. 370-376 ◽  
Author(s):  
Xiaomao Zhao ◽  
Yuxin Wen ◽  
Jian Zhao ◽  
Dong Zhao
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation

Digital Image Correlation as a Tool for Monitoring Crack Networks on the Surface of MgO-Based Refractory Castables

2014 ◽  
Vol 92 ◽  
pp. 242-247
Author(s):  
Rafael G.M. Saracura ◽  
Rodrigo B. Canto ◽  
Victor Carlos Pandolfelli ◽  
Nicolas Schmitt ◽  
François Hild
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Digital Camera ◽  
Experimental Results ◽  
Image Correlation ◽  
Post Processing ◽  
Climatic Chamber ◽  
Refractory Castables

This paper deals with the characterization of crack networks on the surface of refractory castable slabs, which are induced by stresses arising during the curing and drying (CD) stages. Images of the surface of castable samples placed in a house-made climatic chamber were recorded during the CD stages with a digital camera and processed by Digital Image Correlation (DIC) tomeasure the displacement field. Post-processing of DIC results were performed to estimate the length, orientation and opening of cracks in networks. The methodology is detailed and first analyses of experimental results are shown.

Metoda DIC

BUILDER ◽  
2019 ◽  
Vol 259 (2) ◽  
pp. 66-68
Author(s):  
Dorota Marcińczak
Keyword(s):  
Composite Materials ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Concrete Beam ◽  
Correlation Method ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Strain Gauges ◽  
Reference Image

DIC (DIGITAL IMAGE CORRELATION) METHOD IN THE RESEARCH OF RC BEAMS STRENGTHENED WITH PBOFRCM MATERIALS. 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.

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

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
M. Arza-García ◽  
C. Núñez-Temes ◽  
J. A. Lorenzana ◽  
J. Ortiz-Sanz ◽  
A. Castro ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Field Measurements ◽  
Image Correlation ◽  
Strain Gauges ◽  
Source Image ◽  
Full Field ◽  
Cost Approach

AbstractDue 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.

A low-cost digital image correlation based constitutive sensor

2010 ◽  
Author(s):  
Gun-Jin Yun ◽  
Shen Shang ◽  
Shilpa Kunchum ◽  
Joan Carletta ◽  
Si-Byung Nam
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Low Cost ◽  
Image Correlation

Understanding the effect of weathering on adhesive bonds for wood composites using digital image correlation (DIC)

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Paige McKinley ◽  
Arijit Sinha ◽  
Frederick A. Kamke
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Load ◽  
Image Correlation ◽  
Wood Composites ◽  
Shear Tests ◽  
Adhesive Bonds ◽  
Shear Moduli ◽  
Lap Shear

Abstract The quality of wood composites is dependent on the bondlines’ performance and their moisture resistance. The effect of moisture intrusion into bondlines is the focus of this study. The strain profile in the bondline during loading was investigated and the effects of weathering on the bondline were quantified by digital image correlation (DIC), while load deflection data were collected from lap-shear tests (LShTs). A total of 75 LShTs were evaluated including four different adhesive types with Douglas-fir wood, out of which 39 served as controls and 36 as substrates for weathering. The effect of weathering on failure load was not statistically significant. Only the bonded surface and adhesive type have significant effects on failure load, as well as the three-way interaction between the bonded surface, adhesive, and weathering, as revealed by three-way analysis of variance (ANOVA). The average effective shear moduli for the weathered samples were significantly lower than those for the control samples.

A Low-Cost and Simplified Digital Image Correlation Software Package for Use in Undergraduate Teaching Laboratories

2016 ◽  
Author(s):  
Fritz Hieb ◽  
Michael Hargather
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Low Cost ◽  
Image Correlation ◽  
Undergraduate Teaching ◽  
Development Cycle ◽  
Undergraduate Laboratory ◽  
And Performance ◽  
As Stress

Digital image correlation (DIC) has become an industry staple quickly replacing classic techniques. High-speed images are taken of a material sample being deformed, then algorithms applied to calculate variables of sample deformation such as stress, strain, displacement and displacement velocity. Currently, the analysis technology is not available at the level of simplicity and accessibility needed to teach the methods in an undergraduate laboratory. This project aims to develop a single program to perform DIC that is simple to use, accurate, and available at low cost. This paper describes the state of current DIC algorithm research, drawbacks of available technologies, the development cycle of the software including the techniques used to obtain the necessary accuracy and performance, and a demonstration of the DIC functionality in comparison to results obtained from commercial software.

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