scholarly journals Multi-scale experimental study of creep-fatigue failure initiation in a 709 Stainless Steel alloy using high resolution digital image correlation. Final report

2020 ◽  
Author(s):  
John Lambros
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
High Resolution ◽  
Digital Image Correlation ◽  
Image Correlation ◽  
Final Report ◽  
Steel Alloy ◽  
Failure Initiation ◽  
Multi Scale ◽  
Creep Fatigue

scholarly journals Super Resolution Digital Image Correlation (SR-DIC): an Alternative to Image Stitching at High Magnifications

2021 ◽  
Author(s):  
R. S. Hansen ◽  
D. W. Waldram ◽  
T. Q. Thai ◽  
R. B. Berke
Keyword(s):  
High Resolution ◽  
Digital Image Correlation ◽  
Spatial Resolution ◽  
Digital Image ◽  
Super Resolution ◽  
Image Correlation ◽  
Low Resolution ◽  
Strain Measurements ◽  
Resolution Image ◽  
High Resolution Image

Abstract Background High-resolution Digital Image Correlation (DIC) measurements have previously been produced by stitching of neighboring images, which often requires short working distances. Separately, the image processing community has developed super resolution (SR) imaging techniques, which improve resolution by combining multiple overlapping images. Objective This work investigates the novel pairing of super resolution with digital image correlation, as an alternative method to produce high-resolution full-field strain measurements. Methods First, an image reconstruction test is performed, comparing the ability of three previously published SR algorithms to replicate a high-resolution image. Second, an applied translation is compared against DIC measurement using both low- and super-resolution images. Third, a ring sample is mechanically deformed and DIC strain measurements from low- and super-resolution images are compared. Results SR measurements show improvements compared to low-resolution images, although they do not perfectly replicate the high-resolution image. SR-DIC demonstrates reduced error and improved confidence in measuring rigid body translation when compared to low resolution alternatives, and it also shows improvement in spatial resolution for strain measurements of ring deformation. Conclusions Super resolution imaging can be effectively paired with Digital Image Correlation, offering improved spatial resolution, reduced error, and increased measurement confidence.

Camera array-based digital image correlation for high-resolution strain measurement

2018 ◽  
Vol 89 (10) ◽  
pp. 105110 ◽  
Author(s):  
Xinxing Shao ◽  
Zhenning Chen ◽  
Xiangjun Dai ◽  
Xiaoyuan He
Keyword(s):  
High Resolution ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Measurement ◽  
Image Correlation ◽  
Camera Array

scholarly journals Development of High-Fidelity Imaging Procedures to Establish the Local Material Behavior in Friction Stir Welded Stainless Steel Joints

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 592
Author(s):  
S. Ramachandran ◽  
A. Lakshminarayanan ◽  
P. Reed ◽  
J. Dulieu-Barton
Keyword(s):  
Stainless Steel ◽  
High Resolution ◽  
Microstructural Characterization ◽  
Local Strain ◽  
Material Behavior ◽  
Image Correlation ◽  
Full Field ◽  
Friction Stir ◽  
2D Digital Image Correlation ◽  
304 Austenitic Stainless Steel

Friction stir welded (FSW) 304 austenitic stainless steel (SS) joints are studied using a range of microstructural characterization techniques to identify various sub-regions across the weld. A high-resolution (HR) 2D-digital image correlation (DIC) methodology is developed to assess the local strain response across the weld surface and cross-section in the elastic regime. The HR-DIC methodology includes the stitching of multiple images, as it is only possible to partially cover the FSW region using a single camera with the high-resolution optical set-up. An image processing procedure is described to stitch the strain maps as well as strain data sets that allow full-field strain to be visualized and interrogated over the entire FSW region. It is demonstrated that the strains derived from the DIC can be associated with the local weld geometry and the material microstructure in the region of the FSW. The procedure is validated in the material elastic range and provides an important first step in enabling detailed mechanical assessments of the local effects in the FSW process.

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