scholarly journals Analysis of Wave-Induced Current Using Digital Image Correlation Techniques

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Bumshick Shin ◽  
KyuHan Kim

Recently, advancement of digital image techniques and communications technology has enabled the application of existing images for scientific purposes. Furthermore, both quantitative and qualitative analyses of images have become possible through image processing such as transmit/storage of digital image data and image rectification. In this study, a coast having representative characteristics of east coast of Korea was selected with having erosion in winter, and the sedimentation in summer takes place repeatedly. Three-dimensional hydraulic model test was conducted to analyze its outcomes by a digital image correlation technique in order to understand the wave-induced current affecting the sediment transport. For this study, images filmed by the high-sensitive and high-resolution video camera were converted into stopped images of regular intervals and then those converted images were used for the following procedure to analyze flow and velocity into digital coordinates. The outcomes from interpretation of images filmed by the high-sensitive and high-resolution video camera can be utilized as a very useful analysis method for appreciating the generation mechanism and movement route of longshore current and rip current.

2019 ◽  
Vol 8 (4) ◽  
pp. 564-575 ◽  
Author(s):  
Weiguo Mao ◽  
Yujie Wang ◽  
Jun Shi ◽  
Huiyu Huang ◽  
Yuncheng Wang ◽  
...  

AbstractIt is important to investigate the mechanical performances of (Gd0.9Yb0.1)2Zr2O7 (GYbZ) materials deposited on irregular substrates for improving new thermal barrier coatings. Three-point bending fracture characteristics of freestanding GYbZ coating prepared by supersonic plasma sprayed (SPS) technique were investigated with the help of digital image correlation technique. The cracking time, crack propagation path, and mechanical properties of GYbZ coating were obtained. Meanwhile, the X-ray computed tomography technique was introduced to scan the microstructure of freestanding GYbZ coatings, which are used to establish three-dimensional (3D) finite element model by using the Avizo software. The brittle cracking criterion was applied to describe the bending fracture process of GYbZ coatings. The critical cracking strain was estimated as 0.36%±0.03% by repeatedly comparing the difference between the experimental and simulated curves. The results would be extended to predict the dangerous region and failure mechanisms of GYbZ coatings deposited on irregular substrate during finite element simulations.


Author(s):  
R. S. Hansen ◽  
D. W. Waldram ◽  
T. Q. Thai ◽  
R. B. Berke

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.


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