Study of the nucleation and development of deformation bands at the vertex of a notch by the method of holographic interferometry

In the study described, holographic interferometry (based on comparing two or more light-wave fronts, one of which corresponds to the initial state and the other(s) to the deformed state of the object) was used to visualize the development of deformation bands at notches. Holographic interference patterns of specimens with various notches are given and discussed. It is shown that the method makes it possible to determine the lower bound of loads at which elastic and elastoplastic strains arise at crack and notch type strain raisers and to study the behavior of the strains in the plastic region and in fracture.