Finite Element Analysis of Crack Propagation in Precise Separation Process of Tubing Eccentric Loading Fatigue Fracture

Aiming at the difficulties of efficient and precise separation of metal tubes. For tubing fatigue fracture precision separation, this paper proposes a tubing precision separation process under eccentric wheel rotational bending fatigue loading. Mechanical properties experiments for 304 stainless steel tubing are carried out. On this basis, the J-C constitutive model of 304 stainless steel tubing fatigue fracture is established. In addition, the tubing stress at different rotation angles of the eccentric wheel and the axial stress at four positions of the tubing V-groove section are analyzed, and the process of the tubing precision separation is simulated. According to the results, the axial stress of the tubing V-groove section changes basically symmetrically, and the stress is the largest at the smallest distance from the eccentric wheel excircle axis. During fatigue loading cycles from 0 to 500, the crack growth rate of tubing outer ring is greater than that of the inner ring. With the increase in loading cycles, the crack surface gradually changes from smooth to undulating. Finally, an obvious final fracture region appears, which is consistent with the experimental results.