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 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.

Local Elasto-Plastic Identification of the Behaviour of Friction Stir Welds with the Virtual Fields Method

2011 ◽  
Vol 70 ◽  
pp. 135-140 ◽  
Author(s):  
G. Le Louëdec ◽  
M.A. Sutton ◽  
Fabrice Pierron
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Weld Zone ◽  
Spatial Variations ◽  
Image Correlation ◽  
Virtual Fields Method ◽  
Full Field ◽  
Friction Stir

Welding is one of the most popular joining technologies in industry. Depending on the materials to be joined, the geometry of the parts and the number of parts to be joined, there is a wide variety of methods that can be used. These joining techniques share a common feature: the material in the weld zone experiences different thermo-mechanical history, resulting in significant variations in material microstructure and spatial heterogeneity in mechanical properties. To optimize the joining process, or to refine the design of welded structures, it is necessary to identify the local mechanical properties within the different regions of the weld. The development of full-field kinematic measurements (digital image correlation, speckle interferometry, etc.) helps to shed a new light on this problem. The large amount of experimental information attained with these methods makes it possible to visualize the spatial distribution of strain on the specimen surface. Full-field kinematic measurements provide more information regarding the spatial variations in material behaviour. As a consequence, it is now possible to quantify the spatial variations in mechanical properties within the weld region through a properly constructed inverse analysis procedure. High speed tensile tests have been performed on FSW aluminium welds. The test was performed on an MTS machine at a cross-head speed of up to 76 mm/s. Displacement fields were measured across the specimen by coupling digital image correlation with a high-speed camera (Phantom V7.1) taking 1000 frames per second. Then, through the use of the virtual fields method it is possible to retrieve the mechanical parameters of the different areas of the weld from the strain field and the loading. The elastic parameters (Young’s modulus and Poisson’s ratio) are supposed to be constant through the weld. Their identification was carried out using the virtual fields method in elasticity using the data of the early stage of the experiment. Assuming that the mechanical properties (elastic and plastic) of the weld are constant through the thickness, the plastic parameters were identified on small sections through the specimen, using a simple linear hardening model. This method leads to a discrete identification of the evolution of the mechanical properties through the weld. It allows the understanding of the slight variations of yield stress and hardening due to the complexity of the welding process.

Identification of the Mechanical Properties of High-Strength Steel Using Digital Image Correlation

2014 ◽  
Vol 980 ◽  
pp. 122-126 ◽  
Author(s):  
Michaela Štamborská ◽  
Miroslav Kvíčala ◽  
Monika Losertová
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
High Strength Steel ◽  
Strain Field ◽  
High Strength ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Large Strains ◽  
Identification Procedure

Identification of the mechanical properties of high-strength steel using digital image correlation. In this paper an experimental procedure to identify the plastic behaviour of sheet metals up to large strains using full field measurement is presented. The tests were conducted on notched specimens. This geometry generates a heterogeneous strain field which was measured during the test using a digital image correlation system. The advantage of using a heterogeneous strain field in the identification procedure is that a complex state of stress-strain can be analyzed at the same time and much more information can be obtained in a single test. On the other hand, the stress field cannot be directly computed from the test and a suitable identification procedure must be developed. Here, the virtual fields method (VFM) adapted for large strains and plasticity was used to identify the hardening behaviour and the anisotropy of the material. The values obtained with the VFM were compared with the results from a standard identification made using uniaxial tensile tests.

scholarly journals Testing System for the Mechanical Properties of Small-Scale Specimens Based on 3D Microscopic Digital Image Correlation

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3530
Author(s):  
Xu Liu ◽  
Rongsheng Lu
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Three Dimensional ◽  
Image Correlation ◽  
Field Strain ◽  
Small Scale ◽  
Testing System ◽  
Shape Functions ◽  
Full Field

The testing of the mechanical properties of materials on a small scale is difficult because of the small specimen size and the difficulty of measuring the full-field strain. To tackle this problem, a testing system for investigating the mechanical properties of small-scale specimens based on the three-dimensional (3D) microscopic digital image correlation (DIC) combined with a micro tensile machine is proposed. Firstly, the testing system is described in detail, including the design of the micro tensile machine and the 3D microscopic DIC method. Then, the effects of different shape functions on the matching accuracy obtained by the inverse compositional Gauss–Newton (IC-GN) algorithm are investigated and the numerical experiment results verify that the error due to under matched shape functions is far larger than that of overmatched shape functions. The reprojection error is shown to be smaller than before when employing the modified iteratively weighted radial alignment constraint method. Both displacement and uniaxial measurements were performed to demonstrate the 3D microscopic DIC method and the testing system built. The experimental results confirm that the testing system built can accurately measure the full-field strain and mechanical properties of small-scale specimens.

scholarly journals Scheimpflug Camera-Based Stereo-Digital Image Correlation for Full-Field 3D Deformation Measurement

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Cong Sun ◽  
Haibo Liu ◽  
Yang Shang ◽  
Shengyi Chen ◽  
Qifeng Yu
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Rigid Motion ◽  
Deformation Measurement ◽  
Image Correlation ◽  
Depth Of Field ◽  
Full Field ◽  
Scheimpflug Camera ◽  
3D Deformation ◽  
Stereo Digital Image Correlation

To further extend the scope of stereo-digital image correlation (stereo-DIC) to more challenging environments, a novel Scheimpflug camera-based stereo-DIC is developed for full-field 3D deformation measurement, wherein the Scheimpflug condition, consisting of tilting the sensor plane with respect to the lens plane for the sake of larger depth of field (DOF) of the camera, is employed. The geometric imaging model of the Scheimpflug camera is described, on the basis of which a robust and effective stepwise calibration strategy is performed to calculate the intrinsic and extrinsic parameters of the stereo Scheimpflug rig. With the aid of a specially tailored stereo triangulation method and well-developed subset-based DIC algorithms, the three-dimensional shape and displacement of the specimen can be retrieved. Finally, practical experiments, including rigid motion tests and three-point bending tests, demonstrate the effectiveness and accuracy of the proposed approach.

Sign in / Sign up

Export Citation Format

Share Document