Submicron deformation field measurements: Part 2. Improved digital image correlation

1998 ◽  
Vol 38 (2) ◽  
pp. 86-92 ◽  
Author(s):  
G. Vendroux ◽  
W. G. Knauss
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Field Measurements ◽  
Deformation Field ◽  
Image Correlation

scholarly journals Multiscale displacement field measurements of compressed mineral-wool samples by digital image correlation

2002 ◽  
Vol 41 (32) ◽  
pp. 6815 ◽  
Author(s):  
François Hild ◽  
Bumedijen Raka ◽  
Maud Baudequin ◽  
Stéphane Roux ◽  
Florence Cantelaube
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Field Measurements ◽  
Mineral Wool ◽  
Image Correlation

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.

Measurement and Analysis of Concrete Deformation Field Based on CT and Digital Image Correlation Method

2020 ◽  
Vol 57 (20) ◽  
pp. 200401
Author(s):  
王凡 Wang Fan ◽  
赵亮 Zhao Liang ◽  
吴晓东 Wu Xiaodong ◽  
党发宁 Dang Faning
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Deformation Field ◽  
Image Correlation ◽  
Digital Image Correlation Method ◽  
Measurement And Analysis

Stress Field Analysis in Orthogonal Cutting Process Using Digital Image Correlation Technique

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Dong Zhang ◽  
Xiao-Ming Zhang ◽  
Wen-Jie Xu ◽  
Han Ding
Keyword(s):  
Digital Image Correlation ◽  
Stress Field ◽  
Elastic Deformation ◽  
Digital Image ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Deformation Field ◽  
Machining Process ◽  
Image Correlation ◽  
Dic Technique

Cutting stress field in machining process plays a significant role in the understanding of cutting mechanics and prediction of surface integrity, tool wear, and failure. It is in great need to get accurate and reliable cutting stresses in the chip formation zone. In this paper, a new methodology to obtain the cutting stress field is proposed. The deformation field containing elastic as well as plastic parts can be obtained via digital image correlation (DIC) technique. The orthogonal cutting stress field can be obtained with the experimental determined deformation field and material constitutive model as inputs. However, the challenge is to handle the inaccuracy of infinitesimal elastic deformation involved in the total deformation due to the inaccuracy of the obtained images. We develop a method to modify the hydrostatic pressure field based on mechanical equilibrium equations to compensate the inaccuracy of elastic deformation part. Besides, Eulerian logarithmic strain based on a least square plane fit on a subset of displacement data is adopted to reduce the image noise. The stress distribution along the shear plane and tool–chip interface can be extracted and integrated to calculate cutting forces. A feasibility study is performed by comparing the cutting forces predicted based on this new method against the experimental measurements. The comparison of cutting parameters obtained through DIC technique with finite element method (FEM) predictions is also made.

scholarly journals A Method for Calibrating a Digital Image Correlation System for Full-Field Strain Measurements during Large Deformations

2019 ◽  
Vol 9 (14) ◽  
pp. 2828 ◽  
Author(s):  
Robert Blenkinsopp ◽  
Jon Roberts ◽  
Andy Harland ◽  
Paul Sherratt ◽  
Paul Smith ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Large Deformations ◽  
Speckle Pattern ◽  
Field Measurements ◽  
Image Correlation ◽  
Field Strain ◽  
Full Field ◽  
Error Distributions ◽  
Multiple Deformation

Numerous variables can introduce errors into the measurement chain of a digital image correlation (DIC) system. These can be grouped into two categories: measurement quality and the correlation principle. Although previous studies have attempted to investigate each error source in isolation, there are still no comprehensive, standardized procedures for calibrating DIC systems for full-field strain measurement. The aim of this study, therefore, was to develop an applied experimental method that would enable a DIC practitioner to perform a traceable full-field measurement calibration to evaluate the accuracy of a particular system setup in a real-world environment related to their specific application. A sequence of Speckle Pattern Boards (SPB) that included artificial deformations of the speckle pattern were created, allowing for the calibration of in-plane deformations. Multiple deformation stages (from 10% to 50%) were created and measured using the GOM ARAMIS system; the results were analysed and statistical techniques were used to determine the accuracy. The measured strain was found to be slightly over-estimated (nominally by 0.02%), with a typical measurement error range of 0.34% strain at a 95% confidence interval. Location within the measurement volume did not have a significant effect on error distributions. It was concluded that the methods developed could be used to calibrate a DIC system in-situ for full-field measurements of large deformations. The approach could also be used to benchmark different DIC systems against each other or allow operators to better understand the influence of particular measurement variables on the measurement accuracy.

The Deformation Habits of Compressed Open-Cell Solid Foams

2000 ◽  
Vol 122 (4) ◽  
pp. 376-378 ◽  
Author(s):  
Y. Wang ◽  
G. Gioia ◽  
A. M. Cuitin˜o
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Displacement Field ◽  
Field Measurements ◽  
Image Correlation ◽  
Correlation Technique ◽  
Digital Image Correlation Technique ◽  
Open Cell ◽  
Spatially Inhomogeneous ◽  
Solid Foams

Compressed open-cell solid foams frequently exhibit spatially inhomogeneous distributions of local stretch. The theoretical aspects of this deformation habit have not been clearly elucidated. Here we briefly discuss the energetics of the problem to show that the stretch inhomogeneity stems from the nonconvexity of the underlying potential. We also perform displacement field measurements using the Digital Image Correlation technique, and discuss the results in light of the theory. [S0094-4289(00)01904-6]

scholarly journals Identification of a macroscopic anisotropic damage model using digital image correlation and the equilibrium gap method

2010 ◽  
pp. 229-240
Author(s):  
Laurent Crouzeix ◽  
Jean-Noël Périé ◽  
Francis Collombet ◽  
Bernard Douchin
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Damage Model ◽  
Field Measurements ◽  
Image Correlation ◽  
Anisotropic Damage ◽  
Biaxial Test ◽  
Displacement Fields ◽  
Full Field ◽  
Constitutive Parameters

The aim of the work is to demonstrate how an anisotropic damage model may be identified from full field measurements retrieved during a heterogeneous test. The example of a biaxial test performed on a 3D C / C composite is used. In a first step, the displacement fields measured by classical Digital Image Correlation are used as input data of a finite difference version of the Equilibrium Gap Method. A benefit from unloadings (assumed to be elastic) is shown to retrieve a damage law. In a second step, inelastic strains can be assessed from the total measured strain and the elastic estimated strains. The constitutive parameters relative to the inelastic part of the model are then identified.

Sign in / Sign up

Export Citation Format

Share Document