構造用鋼材におけるディンプル破断面の統計的評価

抄録

A statistical analysis of ductile fracture surface has been made on a structural steel. Both the notched specimens with different notch acuity and the unnotched specimens were employed to obtain a wide range of stress triaxiality. A large number of dimples were examined to clarify the statistics of dimple size distribution. The ductile fracture surface was compased of variously sized dimples, and the dimple size distributions were expressed approximately by the composite Weibull distribution. Whereas, the extreme value plots of the maximum dimple size has been applied to characterize the statistical variation on the extensive ductile fracture surfaces. A clearly defined change in the ductile fracture surfaces associated with fracture strain was well expressed by plotting the distributions of the maximum dimple size in a given unit area on the extreme probability paper. Then, it should be noted that the extreme value analysis would be quite useful for quantitative fractographic analysis of ductile fracture surfaces.