SOLUTION OF STRESS-CORROSION CRACK PROBLEMS BY THE METHOD OF CAUSTICS

Since its appearance more than 20 years ago, the optical method of caustics has been used extensively for the solution of a host of static and dynamic problems in fracture mechanics. In the present work, the applicability of the method of caustics to the solution of stress-corrosion crack problems is briefly reviewed. As was recently pointed out, the changing state of stress in the neighbourhood of the crack tip from plane strain at the tip to plane stress at a critical distance from the tip should seriously be taken into account in the evaluation of the optical patterns. This condition is even more critical in stress-corrosion crack problems, due to the rapidly changing specimen thickness because of the corrosive environment. We provide a thorough discussion of the limits of applicability of the method of caustics in stress-corrosion crack problems.