Optimisation of the optical method of caustics for the determination of stress intensity factors

Abstract A detailed guide to the practical application of the optical method of caustics to stress intensity factor measurement is provided which should prove invaluable to the experimenter using this technique. A thorough error analysis is given highlighting a collimated incident beam arrangement as the optimum configuration for generating caustic measurements. Other sources of experimental error which are not immediately apparent, such as the quality of the incident beam, specimen surface preparation and the alignment of the specimen loading fixture are also considered.