Abstract
Digital image correlation (DIC) is a popular photomechanics method for deformation measurement. The conventional subset-based DIC method obtains the displacement vectors at the subset centers, but cannot calculate the deformation on the specimen edges, which may contain very useful information because specimens usually have greater deformation on edges, especially on curved edges due to stress concentration. In this study, the capability of a mesh-based DIC method using 8-node quadrilateral elements (Q8-mesh-DIC) in boundary deformation measurement was investigated and highlighted for specimens with non-uniform deformation. The results were compared with those obtained by some conventional subset-based DIC methods, and the accuracy of the boundary deformation measurement was verified through simulated and real experiments. The Q8-mesh-DIC appears to be more suitable for the boundary deformation measurement of non-uniform deformation fields.
Highlights
Introduction tion Measurement by MeshBased Dig-The digital image correlation (DIC) method [1], known as the digital speckle correlation method, is a non-contact photomechanics method based on the analysis of speckle images
The results demonstrated that the calculation accuracy of Q8-DIC in deformation measurement near curved edges was much higher than those of the extrapolation and half-subset methods
The conventional subset-based DIC method exhibits a fundamental defect in boundary deformation calculation
Summary
In such cases, errors will be induced in the correlation and interpolation calculation. To form the deformed image, random Gaussian noise with a gray-scale intensity variance of 4 was added to the reference image Based on these two images, the displacement field was calculated with subset sizes ranging from 11 × 11 to 77 × 77 pixels, with an interval of 6 pixels. As no actual deformation occurred, the SD error of the measured displacement field can be expressed as v u u σ=t
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
