An automated two-view method for determining strain distributions on deformed surfaces

A new approach to surface strain measurement is described in which two complete views of an object are digitized in two dimensions using either a photographic or an automated vision system, corresponding points are identified, and the three-dimensional coordinates are determined from the relationship between the views. Strains are computed in each triangular region into which the surface is divided based on the assumption of pure homogeneous deformation in each triangle, and the strain contours are displayed graphically on the deformed geometry. Results are presented and discussed in terms of known sources of error.