Cutting simulation capabilities based on crystal plasticity theory and discrete cohesive elements

A material microstructure-level (MML) cutting model based on the crystal plasticity theory is adopted for modelling the material removal by orthogonal cutting of the Titanium alloy Ti6Al4V. In this model, the grains are explicitly taken into account, and their orientation angles and slip system strength anisotropy are considered as the main source of the microstructure heterogeneity in the machined material. To obtain the material degradation process, the continuum intra-granular damage model and the discrete cohesive zone inter-granular damage model have been implemented. Zero thickness cohesive elements are introduced to simulate the bond between grain interfaces. The material model is validated by the simulation of a compression test and results are compared with experimental data from the literature. Simulation results demonstrate the ability of the MML cutting model to capture the influence of the material microstructure, in terms of initial grain orientation angles (GOA), on chip formation and machined surface integrity.