A theory of caustics for mixed-mode fast running cracks. (2nd report. General mixed-mode theory).

Abstract

In the previous paper, a theory of caustics was developed for elastodynamically propagating cracks under an inplane mixed-mode condition. A new procedure was also proposed for the evaluation of the dynamic stress intensity factors. In this paper, the theory of caustics was also extended for dynamically propagating cracks under general mixed-mode conditions including modes I, II and III. Complex potentials for the general solutions of the near-tip field which have been previously derived by the authors were used in this theoretical development. The effects of crack velocity and the mixed-mode condition on the caustic pattern and the initial curve were investigated. It was found that even a small magnitude of the mode III loading influences the shape of the caustic pattern. The deformed surface around a crack tip under the above condition was also clarified.