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Published February 2019 | public
Journal Article

Augmented Lagrangian Digital Image Correlation


Digital image correlation (DIC) is a powerful experimental technique for measuring full-field displacement and strain. The basic idea of the method is to compare images of an object decorated with a speckle pattern before and after deformation, and thereby to compute the displacement and strain fields. Local subset DIC and finite element-based global DIC are two widely used image matching methods. However there are some drawbacks to these methods. In local subset DIC, the computed displacement field may not be compatible, and the deformation gradient may be noisy, especially when the subset size is small. Global DIC incorporates displacement compatibility, but can be computationally expensive. In this paper, we propose a new method, the augmented-Lagrangian digital image correlation (ALDIC), that combines the advantages of both the local (fast) and global (compatible) methods. We demonstrate that ALDIC has higher accuracy and behaves more robustly compared to both local subset DIC and global DIC.

Additional Information

© Society for Experimental Mechanics 2018. Received: 19 February 2018; Accepted: 9 November 2018; First Online: 06 December 2018. We are grateful to Dr. Louisa Avellar for sharing her images of heterogeneous fracture with us. We gratefully acknowledge the support of the US Air Force Office of Scientific Research through the MURI grant 'Managing the Mosaic of Microstructure' (FA9550-12-1-0458).

Additional details

August 22, 2023
October 19, 2023