The Significance of Plastic Zone Growth under Cyclic Loading and Crack Opening/Closing Model in Fatigue Crack Propagation
Fatigue cracks remain closed at lower loading level during a part of load cycle even though a tension-to-tension loading is applied. The crack closure plays a role to obstruct the generation and growth of compressive plastic zone during unloading. Cyclic plastic work, which corresponds to an irreversible energy consumed in a cracked body is generated ahead of a crack, is required as a fatigue crack driving force. The amout of cyclic plasticity is reduced by a crack closure. The crack opening/closing model based on the Dugdale model under arbitrary stress distributions for a through thickness straight crack is proposed and the fatigue crack growth under various loadings is investigated.
M. Toyosada and K. Gotoh, "The Significance of Plastic Zone Growth under Cyclic Loading and Crack Opening/Closing Model in Fatigue Crack Propagation", Materials Science Forum, Vol. 482, pp. 95-102, 2005