Research on critical loading force in precision cropping system based on hydraulic compensation

In order to solve the sudden change of critical loading force before and after the crack initiation at the tip of V-shaped notch and improve the quality of cropping section, it is proposed that the fracture process of the bar is divided into two stages: the crack initiation stage and the crack propagation stage. The research results show that the influence of bottom corner radius s of V-shaped notch on mutation coefficient Fp0.2/Fci is the largest; when s is equal to 0.12 mm, there is no force mutation. Based on it, the variable frequency-loading curve is designed in this paper, by which the high-quality cross-section is obtained.153