Optically exact equations of caustics for slant cracks biaxially loaded

The equations of caustics have been derived based on the exact theory of geometrical optics, and they have been adapted to the problem of a slanting internal crack in a disk under biaxial loading. A comparison of the exact caustics with those derived from the far-field theory used in the past in the applications showed negligible difference between the two theories. Thus, it is shown that the approximate theory of caustics used before for determining singular fields in mechanics is sufficiently accurate for engineering applications.