1 December 2003 Measurement of J integral by shadow spot generated from out-of-plane displacement
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Optical Engineering, 42(12), (2003). doi:10.1117/1.1622706
The out-of-plane displacement field at the crack tip region of a compact tension specimen is measured by stereo vision and used to generate a shadow spot on the virtual screen placed behind the specimen by using the mapping equation of reflected caustics. The J values are then computed using the maximum transverse diameter of the generated shadow spot. In the experiment, the in-plane displacement data are also recorded to obtain J measurements along contours surrounding the crack tip. Results indicate that for crack extensions up to 0.275 mm, the J values evaluated using the generated shadow spot are in good agreement with the measurements from the in-plane displacement data and the Merkle-Corten formula. However, the J values obtained using in-plane displacement data are still close to the Merkle-Corten results, even when the crack growth of Δa≈4.0 mm is reached.
Perng-Fei Luo, C.-K. Chuang, Yuh J. Chao, "Measurement of J integral by shadow spot generated from out-of-plane displacement," Optical Engineering 42(12), (1 December 2003). http://dx.doi.org/10.1117/1.1622706


Optical engineering

Computed tomography

3D image processing

Stereo vision systems


Image processing

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