A 2.5D C/C composite cutting force prediction model based on brittle fracture mechanism

The C/C composite is a kind of composite with both functional and structural characteristics. It maintains the excellent physical and mechanical properties of the carbon matrix and fibers. Aiming at the low strength of C/C composite, the needle punching technology introduces fibers for reinforcement, which is called 2.5D C/C composite. In this paper, a 2.5D C/C composite cutting force prediction model based on brittle fracture mechanism is developed. Considering pores distribution, it proposes a material removal mechanism in the cutting process of 2.5D C/C composites. The edge indentation experiment is used to investigate the law of crack generation, expansion and path in the cutting process. It is also used to analyze the generation condition of chips with three types. Based on the law of energy conservation in the fracture mechanics theory, the brittle fracture mechanism is studied by introducing the instantaneous cut-in material proportion considering pores distribution. Furthermore, the relationship between the energy release rate of crack growth and the tangential force is established. The orthogonal cutting force model is derived according to the relationship. To validate the developed model and calibrate the correlation coefficients of the cutting force model, the orthogonal cutting experiment are performed. The pores distribution of the actual and simulated surface is analyzed by evaluating the probability density and the cumulative distribution function. Moreover, the average error for the cutting force prediction with the developed model is 8.62%.