On the correction by McClintock and Irwin

In the case of quasi-brittle fracture, at the crack tip there is a small plastic region whose affection cannot be neglected. Therefore the linear elastic asympototic fields must be corrected. In 1965 F. A. McClintock and G. R. Irwin presented a correction which since then has been adopted extensively. Here in this paper, it must be pointed out that such correction is wrong. A correct result is given.Communicated by Chien Wei-zang.