Research of stress intensity factor of V-shaped notch tip in precision cropping.

For carrying out the precise cropping of metal bar with different geometrical sizes, it is very important to obtain the reasonable stress intensity factor of V-shaped notch tip rapidly and accurately. At first, a new precise cropping method, which is the high-speed peripheral low-stress bending fracture cropping is presented in the paper, and its working mechanism is also given in detail. The stress field near V-shaped notch tip is analyzed, and the stress extrapolation method is presented to compute the stress intensity factor of V-shaped notch tip. Based on it, the correctional expression of theoretical stress intensity factor in a handbook of stress intensity factor is also given. The contrasts between stress intensity factor results obtained by means of the stress extrapolation method and the corresponding theoretical results in the handbook of stress intensity factor are also carried out in detail. The results show that the two errors are not more than 5 % and are within a reasonable engineering range. The cropping experimental results for initial loading force and crack propagation life have also confirmed that the correctional expression of theoretical stress intensity factor is feasible. [ABSTRACT FROM AUTHOR]