Evaluation of Global and Local Deformation Behaviors of Similar Laser Welded Joints using Digital Image Correlation

2014 ◽  
Author(s):  
Li Yanhua ◽  
Jianping Lin
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Welded Joints ◽  
Local Deformation ◽  
Image Correlation ◽  
Deformation Behaviors ◽  
Global And Local

Local Constitutive Behavior of Undermatched Welded Joints in Pipeline Steel Using Digital Image Correlation Technology

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
X. Wu ◽  
J. Shuai ◽  
K. Xu ◽  
Z. Lv
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Welded Joints ◽  
Pipeline Steel ◽  
Image Correlation ◽  
Optical Observations ◽  
Uniaxial Tensile ◽  
Welded Steel ◽  
Steel Joint ◽  
Constitutive Parameters

Abstract Although the identification of local constitutive behaviors is possible based on digital image correlation (DIC), few studies have been reported that characterize the properties of the girth-welded joints of pipeline steel. The DIC technique was used to measure the strain fields of undermatched girth-welded joints of X80 pipeline steel under uniaxial tension in this paper. First, microstructure optical observations and micrometer hardness measurements were used to test the size and hardness of the subregions in the specimens. Second, the local strain data in different regions of the girth-welded joint were obtained via DIC technology, and the stress data were obtained via uniaxial tensile tests. Then, the stress–strain relationships of the weld metal (WM), base metal (BM), and subregions of the heat-affected zone (HAZ) of the girth-welded joints of pipeline steel were obtained. Finally, the constitutive parameters of the Ramberg–Osgood model in the different regions were determined by curve fitting of the strain and stress data. The local yield strength, elastic modulus, and hardening exponent of the welded joints were obtained. The yield stresses of the different subregions of the welded steel joint followed the sequence BM > WM > HAZ, which was consistent with the results of the hardness measurements. The hardening exponents of the different subregions of the welded steel joint followed the sequence HAZ > WM> BM.

Visualization of Strain Distribution on Deformed Steels Using Digital Image Correlation Method

2017 ◽  
Vol 741 ◽  
pp. 138-143 ◽  
Author(s):  
Norimitsu Koga ◽  
Osamu Umezawa
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Distribution ◽  
Ferritic Steel ◽  
Martensitic Steel ◽  
Strain Analysis ◽  
Correlation Method ◽  
Deformation Mode ◽  
Local Deformation ◽  
Image Correlation

Digital image correlation (DIC) method is a convenient strain analysis method calculating strain from the difference of images between before and after deformation and shows an advantage to apply to any deformation mode or materials as long as significant contrast. We reviewed basic principles of DIC method and then demonstrated strain distribution in tensile deformed ferritic steel and cyclic deformed tempered martensitic steel. Strain distribution in tensile deformed ferritic steel becomes inhomogeneous with lowering temperature due to restriction of slip systems at low temperature. Strain distribution around a fatigue crack in cyclic deformed tempered martensitic steel was visualized by DIC analysis for replica film and strain concentrated on crack tip same as previous report in DIC analysis for specimen surface, which suggests that strain distribution obtained from replica film has an enough reliability. From these results, it can be concluded that DIC analysis is effective method to investigate local deformation and relation between local deformation and fracture behavior in metal materials.

Global and local coordinates in digital image correlation

2007 ◽  
Vol 46 (7) ◽  
pp. 1050 ◽  
Author(s):  
Wei Sun ◽  
Chenggen Quan ◽  
Cho Jui Tay ◽  
Xiaoyuan He
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Local Coordinates ◽  
Global And Local
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