Fracture mechanics based on deformation wave theory and its verification with optical interferometry

The goal of this research is to test a theory of deformation and fracture (the field theory) we develop via experiment using the optical technique known as Electronic Speckle Pattern Interferometry (ESPI). The field theory formulates all stages of deformation and fracture on the same theoretical basis. According to this theory, the plastic deformation is represented by an elastoplastic wave. Under a certain condition (the fracturing condition), the elastoplastic wave loses its oscillatory feature, and consequently, the object fractures. ESPI can image the displacement field of an object under deformation in the form of a whole field image consisting of interferometric fringes. The fracturing condition can be found from a certain pattern of the interferometric fringes. In this study, we try to validate the fracturing condition via interferometric fringe analysis by applying a tensile load to the plate specimen.