General Strength Models of Constructional Steel and Fracture Analysis of Notched Bars

Fracture test was performed on 10 notched bars to study fracture mechanism of constructional steel. Test results indicated that plastic deformation concentrated in notch region and crack initiated at center of notched root. Notched bars finally fractured at notched section where stress triaxiality was larger. Fracture mode was combination of shear and normal fracture. According to hydrostatic yield conception of metal, new annotation was given to generalized yield ellipsoidal function of constructional steel. The ellipsoidal fracture function and its parameters were deduced on the assumption that constructional steel yielded and fractured at the same time in tri-axial mean tension stress state. Simulation results of notched bar fracture test showed that fracture took place when the fracture ellipsoidal function reached a critical value.