scholarly journals Application of Digital Image Correlation Technique for the Damage Characteristic of Rock-like Specimens under Uniaxial Compression

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Jing Chai ◽  
Yongliang Liu ◽  
YiBo OuYang ◽  
Dingding Zhang ◽  
Wengang Du
Keyword(s):  
Rock Mass ◽  
Digital Image Correlation ◽  
Uniaxial Compression ◽  
Digital Image ◽  
Sample Surface ◽  
Damage Variable ◽  
Image Correlation ◽  
Full Field ◽  
Plastic Damage ◽  
Damage Process

The damage and degradation are the main influence factors of the instability of rock mass engineering. In this paper, the damage and deformation characteristics of the rock-like samples are investigated under the uniaxial compression test, and the advanced digital image correlation (DIC) device is devoted to full-field deformation data acquisition on the sample surface. Based on the full-field deformation data, a new damage variable is proposed by the principal strain standard deviation to characterize the uniaxial compression damage process of the rock-like samples. The results show that the newly presented damage variable can be utilized for the quantitative characterization of the sample damage. According to the characteristics of the damage variable, the damage evolution process of the rock-like specimens under uniaxial compression can be divided into four stages: initial damage closure stage, linear elastic damage stage, elastic-plastic damage stage, and plastic damage stage. From the stress-strain curve, the cut-off point from elastic to plastic deformation of the rock-like specimen is also the turning point from micro to macro damage; after the point, the apparent initial damage starts to occur on the sample surface; furthermore, the damage of the specimen is accelerated in the plastic damage stage. When the overall damage variable reaches 0.5 or the damage variable of strain localization zone reaches 0.8, the macro crack forms, and the bearing capacity of the rock-like specimen decreases rapidly. The findings are of great significance to the prediction of the damage process of rock mass engineering by digital image correlation.

scholarly journals Brief communication: Full-field deformation measurement for uniaxial compression of sea ice by using the digital image correlation method

2019 ◽  
Author(s):  
Anliang Wang ◽  
Zhijun Wei ◽  
Xiaodong Chen ◽  
Shunying Ji ◽  
Yu Liu ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Sea Ice ◽  
Uniaxial Compression ◽  
Digital Image ◽  
Correlation Method ◽  
Nonlinear Behavior ◽  
Image Correlation ◽  
Mechanical Behaviors ◽  
Full Field

Abstract. We took advantage of digital image correlation to measure the full-field deformation of sea ice in a uniaxial compression experiment in situ. The characteristics of failure mode, nonlinear behavior and crack propagation are all captured by the strain field of specimens. To our knowledge, this is the first attempt to experimentally capture sequential full-field deformations in the mechanical properties of sea ice. This achievement will extend the ability to further explore the complex mechanical behaviors of sea ice.

scholarly journals DIGITAL IMAGE CORRELATION FROM COMMERCIAL TO FOS SOFTWARE: A MATURE TECHNIQUE FOR FULL-FIELD DISPLACEMENT MEASUREMENTS

2018 ◽  
Vol XLII-2 ◽  
pp. 91-95 ◽  
Author(s):  
V. Belloni ◽  
R. Ravanelli ◽  
A. Nascetti ◽  
M. Di Rita ◽  
D. Mattei ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Open Source ◽  
Digital Image ◽  
Structural Engineering ◽  
Sample Surface ◽  
Image Correlation ◽  
Full Field ◽  
Field Displacement ◽  
University Of Rome ◽  
The University

In the last few decades, there has been a growing interest in studying non-contact methods for full-field displacement and strain measurement. Among such techniques, Digital Image Correlation (DIC) has received particular attention, thanks to its ability to provide these information by comparing digital images of a sample surface before and after deformation. The method is now commonly adopted in the field of civil, mechanical and aerospace engineering and different companies and some research groups implemented 2D and 3D DIC software. In this work a review on DIC software status is given at first. Moreover, a free and open source 2D DIC software is presented, named py2DIC and developed in Python at the Geodesy and Geomatics Division of DICEA of the University of Rome “La Sapienza”; its potentialities were evaluated by processing the images captured during tensile tests performed in the Structural Engineering Lab of the University of Rome “La Sapienza” and comparing them to those obtained using the commercial software Vic-2D developed by Correlated Solutions Inc, USA. The agreement of these results at one hundredth of millimetre level demonstrate the possibility to use this open source software as a valuable 2D DIC tool to measure full-field displacements on the investigated sample surface.

scholarly journals Brief communication: Full-field deformation measurement for uniaxial compression of sea ice using the digital image correlation method

2019 ◽  
Vol 13 (5) ◽  
pp. 1487-1494 ◽  
Author(s):  
Anliang Wang ◽  
Zhijun Wei ◽  
Xiaodong Chen ◽  
Shunying Ji ◽  
Yu Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Sea Ice ◽  
Uniaxial Compression ◽  
Digital Image ◽  
Strain Field ◽  
Failure Modes ◽  
Deformation Measurement ◽  
Image Correlation ◽  
Full Field

Abstract. The study of the mechanical properties of sea ice benefits the parameterization of sea-ice numerical models and the optimization of engineering design. Deformation measurement of sea ice has been seen as the essential foundation for the study of these properties. However, this measurement has proved to be difficult due to the complex and nonhomogeneous mechanical properties of sea ice. In this paper, we took advantage of DIC (digital image correlation) to obtain the full-field displacement and strain of sea-ice specimens in a uniaxial compression experiment. Full-field deformations of sea ice under both vertical and horizontal loading were measured. Different mechanical behaviors such as microcracks and failure modes due to the anisotropic properties of sea ice were successfully captured. The nonuniformity and local concentration of the strain field were observed and analyzed. Additionally, we evaluated the displacement and strain field of the specimens to verify the feasibility and accuracy of the method. This successful application provides a convenient and powerful option for the study of sea-ice mechanical properties including failure modes, nonlinear behavior and crack propagation.

scholarly journals Experimental Characterization of the FRCM-Concrete Interface Bond Behavior Assisted by Digital Image Correlation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1154
Author(s):  
Dario De Domenico ◽  
Antonino Quattrocchi ◽  
Damiano Alizzio ◽  
Roberto Montanini ◽  
Santi Urso ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Front Face ◽  
Full Field ◽  
Bond Behavior ◽  
Externally Bonded ◽  
Strengthening Technique ◽  
Concrete Interface

Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a major advantage over contact methods. Additionally, DIC techniques provide full-field maps of response quantities like strains and displacements, unlike traditional methods that are limited to a local investigation. In this work, an experimental application of DIC is presented to investigate a problem of relevant interest in the civil engineering field, namely the interface behavior between externally bonded fabric reinforced cementitious mortar (FRCM) sheets and concrete substrate. This represents a widespread strengthening technique of existing reinforced concrete structures, but its effectiveness is strongly related to the bond behavior between composite fabric and underlying concrete. To investigate this phenomenon, a set of notched concrete beams are realized, reinforced with FRCM sheets on the bottom face, subsequently cured in different environmental conditions (humidity and temperature) and finally tested up to failure under three-point bending. Mechanical tests are carried out vis-à-vis DIC measurements using two distinct cameras simultaneously, one focused on the concrete front face and another focused on the FRCM-concrete interface. This experimental setup makes it possible to interpret the mechanical behavior and failure mode of the specimens not only from a traditional macroscopic viewpoint but also under a local perspective concerning the evolution of the strain distribution at the FRCM-concrete interface obtained by DIC in the pre- and postcracking phase.

The Stress Intensity Factor of Opening Mode Determined by Digital Image Correlation

2011 ◽  
Vol 83 ◽  
pp. 54-59 ◽  
Author(s):  
Rui Zhang ◽  
Ling Feng He ◽  
Chang Rong Li
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Digital Image Correlation ◽  
Intensity Factor ◽  
Digital Image ◽  
Correlation Method ◽  
Compact Tension ◽  
Image Correlation ◽  
Full Field ◽  
Opening Mode

Applications of the digital image correlation method (DIC) for the determination of the opening mode stress intensity factor (SIF) is investigated using an edge cracked aluminum plate in this paper. Standard compact tension test specimen was tested under tensile loading and the full-field displacement fields of the test sample were recorded using DIC. The SIF associated with unavoidable rigid-body displacement translation were calculated simultaneously from the experimental data by fitting the theoretical displacement field using the method of least-squares. Selection of displacement and convergence values is discussed. For validation, the SIF thus determined is compared with theoretical results, confirming the effectiveness and accuracy of the proposed technique. Therefore it reveals that the DIC is a practical and effective tool for full-field deformation and SIF measurement.

scholarly journals Novel Boundary Edge Detection for Accurate 3D Surface Profilometry Using Digital Image Correlation

2018 ◽  
Vol 8 (12) ◽  
pp. 2541 ◽  
Author(s):  
Liang-Chia Chen ◽  
Ching-Wen Liang
Keyword(s):  
Digital Image Correlation ◽  
Edge Detection ◽  
Digital Image ◽  
Optical Diffraction ◽  
Image Correlation ◽  
Detection Accuracy ◽  
Boundary Edge ◽  
Discontinuous Surface ◽  
Full Field ◽  
Surface Profilometry

Digital image correlation (DIC) has emerged as a popular full-field surface profiling technique for analyzing both in-plane and out-of-plane dynamic structures. However, conventional DIC-based surface 3D profilometry often yields erroneous contours along surface edges. Boundary edge detection remains one of the key issues in DIC because a discontinuous surface edge cannot be detected due to optical diffraction and height ambiguity. To resolve the ambiguity of edge measurement in optical surface profilometry, this study develops a novel edge detection approach that incorporates a new algorithm using both the boundary subset and corner subset for accurate edge reconstruction. A pre-calibrated gauge block and a circle target were reconstructed to prove the feasibility of the proposed approach. Experiments on industrial objects with various surface reflective characteristics were also conducted. The results showed that the developed method achieved a 15-fold improvement in detection accuracy, with measurement error controlled within 1%.

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