The equation of caustics in Cartesian coordinates for mixed-mode stress intensity factors

The equation of the classical caustic about. a crack tip in cartesian coordinates (x, y) is derived in the case of mixed-mode stress intensity factors. This is achieved by using the original parametric equations of the caustic and eliminating the parameter (polar angle). Both Groebner basis and resultant algorithms in the computer algebra system Maple V were used for this elimination. The resulting bivariate equation (in cartesian coordinates) is seen to be of the sixth degree exactly, as is also the related equation for mode I stress intensity factors. Copyright (C) 1996 Elsevier Science Ltd.