Diffraction of Light by a Grating Subjected to Homogeneous Strains and Rigid Body Rotations

摘要

A general diffraction-strain theory is developed for the optical diffraction grating strain gages now being used to measure large dynamic strains in solids. General diffraction-strain equations are derived that relate the surface strains to observable changes in a diffraction pattern. Using the Laue diffraction theory, diffraction-strain equations for crossed grating strain gages are derived. Since the current use of the diffraction grating strain gage is to detect plastic strains produced by the axial impact of cylindrical rods, attention is devoted to the development of specific equations and optical configurations for experiments of this type. Several optical configurations for measuring either the axial or the circumferential strain component of the rod are proposed. (Author)