Submicron deformation field measurements: Part 3. Demonstration of deformation determinations

This is the third and last paper in a sequence devoted to an experimental investigation of deformation mechanisms at the submicron scale through the use of a specially designed scanning tunneling microscope. Its application, when used jointly with digital image correlation, as a tool for strain and deformation determinations is explored by way of two demonstrations. First, deformations in a uniaxially stressed, unplasticized (poly)vinylchloride sample are analyzed to yield the three-dimensional surface displacement field over a 10 mu m x 10 mu m area. Homogeneous deformations occur at the micrometer and larger size scales. However, at the 100-nm scale, inhomogeneous deformations embedded in a homogeneous deformation field appear. The second example addresses the deformation field in the vicinity of an interface between a carbon fiber and the surrounding matrix under shear stresses along the fiber. This loading leads to shearing a sheath from the carbon fiber that is about half a micron thick.