Dynamic speckle-interferometry as a tool of mechanics and nondestructive testing

摘要

A problem on the interaction between coherent radiation and a dynamic medium under deformation is studied on the basis of a model of a three-dimensional diffuser. An expression has been obtained for the function of mutual coherence of the intensity of scattered radiation at two spatial-temporal points of free space and the region of the image of a thin object. Some mechanic-optic effects associated with changes, displacements and interferences of speckle fields resulting from the theory are considered. Results of experiments conducted to verify the theory are given, and new coherent-optic methods of measurement and testing are substantiated. Particularly, consideration is given to speckle displacement along the Z-axis in the deformation of a body in the X- and Y- directions, a method for studying rotary motions of surface areas, a method for revealing pre-fracture regions, a method for determining strains and nondestructive testing based on a new approach to the registration of interference fringe patterns.