An evaluation method for brittle fracture from a singular point with arbitrary singularities

• A unified method to evaluate the brittle fracture from a singular point with arbitrary singularity has been proposed.
• From the comparisons with experimental results, the usefulness of proposed method has been verified.
• The effect of high order term in the stress field can be easily taken into account by this method.
• No additional new material׳s property is required in the evaluation.

It is well known that there would be stress singularity different from 1/r near a notch tip or an interfacial edge, and there may be even multiple or oscillatory singularities. The fracture evaluation for such a case is somewhat difficult due to the arbitrary singularities. By adopting the concept of average tangential stress within the characteristic length, an evaluation method is proposed. In this method, only the tensile strength and the fracture toughness are enough to evaluate the fracture from a singular point with arbitrary singularities, no additional new material property is required. That is, no matter what a singular point or what a kind of singularity it is, the fracture can be evaluated in a unified way by this method. The method is examined by the experimental results referenced from the literature, for the cases of kinking fracture from an interface crack tip and fracture from a notch tip with various notch angles. It is found that the theory agrees well with the experimental results.