Extended digital image correlation for full-field deformation measurements: comparison of local and global approaches
Wei Tong (Southern Methodist University)
Eringen Medal Symposium in honor of G. Ravichandran
Mon 4:20 - 5:40
Salomon 001
Digital image correlation (DIC) as a full-field deformation measurement metrology has been developed based on the brightness constancy condition and the deformation continuity condition. The deformation continuity condition over a spatial domain is the key for subpixel displacement measurement precision and it can be imposed by using finite elements in either a local or a global approach. In a conventional local DIC approach, the continuity condition is only applied to stand-alone single-element subsets. In a global DIC approach, the continuity condition is applied to the entire finite element mesh covering the entire spatial domain of interest. When the spatial domain contains cracks, voids or sliding interfaces, the full-field deformation field has often been measured by the extended digital image correlation using so-called extended finite elements in a global approach. In this talk, extended digital image correlation analyses using both local and global approaches will be presented. Similarities and differences of these two approaches will be examined analytically and numerically for full-field deformation measurements of a spatial domain containing certain deformation discontinuities.