Study on the influence of tube surface notch on crack initiation during blanking

In the process of precision tube separation, according to the prefabricated notches on the outer surface of the tube, the notch effects of different types of notches are studied, and the influence of the stress field at the root of the annular V-shaped notch is analyzed. It is determined that the notch angle, notch depth and the radius of the bottom angle of the notch root are the three main parameters that affect the stress field at the root of the notch, and the mathematical expression of the V-notch parameters suitable for tube separation is derived. The design of tube precision separation notch is put forward, and four different notches are numerically simulated. It is concluded that 45° asymmetric V-shaped notch and annular V-shaped notch facing the cutting end are the two notches which are more suitable for the blanking method in this paper. An experimental study is carried out on the crack propagation caused by the notch, and the experimental results are consistent with the numerical simulation results.