A space-time approach in digital image correlation: Movie-DIC

Gilles Besnard (1, 2) , Sandra Guérard (3) , Stéphane Roux (1) , François Hild (1)

1 LMT - Laboratoire de Mécanique et Technologie
2 DAM/DIF - DAM Île-de-France
3 LBM - Laboratoire de biomécanique

A new method is proposed to estimate arbitrary velocity fields from a time series of images acquired by a single camera. This approach, here focused on a single spatial plus a time dimension, is specialized to the decomposition of the velocity field over rectangular shaped (finite-element) bilinear shape functions. It is therefore assumed that the velocity field is essentially aligned along one direction. The use of a time sequence over which the velocity is assumed to have a smooth temporal change allows one to use elements whose spatial extension is much smaller than in traditional digital image correlation based on successive image pairs. This method is first qualified by using synthetic numerical test cases, and then applied to a dynamic tensile test performed on a tantalum specimen. Improvements with respect to classical digital image correlation techniques are observed in terms of spatial resolution.

Mots clés: Digital image correlation; Displacement field; Strain field; Strain rate field; Velocity field; Video

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Gilles Besnard, Sandra Guérard, Stéphane Roux, François Hild. A space-time approach in digital image correlation: Movie-DIC. Optics and Lasers in Engineering, 2011, 49, pp.71-81. ⟨10.1016/j.optlaseng.2010.08.012⟩. ⟨hal-00521203⟩