Effects of notch length on extension behavior of a ductile fracture in a center notched plate of S15CK.

Ductile fracture extension of a notched specimen was investigated by means of the observation of the crack growth behavior on the specimen surface. Correlation between the ductile crack growth and the initial notch length was examined in order to understand the feature of the ductile fracture which was extended by the center crack. In this experiment, the crack growth rate, da /de, for the strain increment depends on the crack length, a, and the value of the nondimensionalized crack growth rate, (da / de) / a, is higher for the short notch length that the long notch length. Crack opening displacement near the crack tip is also dependent on the crack length and the behavior of the crack opening shows a good relation with that of crack growth.