Improvement of Corrective Formula of Plastic Zone Ahead of Crack Tip

The correction of plastic zone ahead of crack tip in the case of small scale yielding is discussed in this paper.The deficiencies of Irwin classical model are pointed out and an improvement is suggested.Based on the exact solution of stress field ahead of the crack tip and the hardening of materials,the improved formula of plastic zone size is presented.The comparison between results of the improved formula and those of Irwin model indicates that improved formula is more reasonable and accurate than Irwin classical model.