Study on the effect of three-dimensional crack initiation and propagation and plastic zone of crack front on fracture-splitting quality of connecting rod

In this study, the initiation and propagation of three-dimensional cracks in the splitting process of fracture-splitting (FS) connecting rods were studied using finite element simulations and actual production based on fracture mechanics theory. Moreover, the influence of the plastic zone of the crack front on the FS quality was also investigated. The stress and strain distribution characteristics of the cracking groove were analyzed, the crack initiation location and process were studied, and the structure and state of the crack front at different stages were described. The results indicated that the crack kink angle increased due to the plastic zone increase, and the crack propagation path and structure changed significantly. The intensification of crack kinks can easily lead to quality defects in cracking processing, because of the increase in the stress intensity factor at the crack front, different stress–strain states, and stress concentration.