Improved optical strain mapping, with detection of strain localization
John Boyle (), Maiko Kume (), Victor Birman (), Robert Pless (), Stavros Thomopoulos (), Guy Genin (Washington University)
Characterization and Imaging of Structural and Material Imperfections
Mon 4:20 - 5:40
Barus-Holley 191
Optical methods are in widespread use for mapping strain fields on deforming solids and structures. The most advanced of these methods involve careful mapping between images of a body in reference and deformed configurations to determine displacement fields, and subsequent differentiation to obtain deformation gradient fields and strain fields. We present a new method to overcome two challenges that arise. The first challenge is the loss of accuracy that can occur with differentiation. The second is ambiguity that arises when strain localization occurs. For the latter, the appearance of regions of localized strains or cracks is often indistinguishable from error associated with estimation of the mapping function, with both producing alternating regions of high and low strains. We will present the new technique, and application to the interpretation of experiments performed on artificial tissues possessing a gradient in mineralization.