A smooth particle hydrodynamic model for two-dimensional numerical simulation of Ti-6Al-4V serrated chip deformation based on TANH constitutive law

摘要

The saw-tooth chip formation is one of the main machining characteristics in cutting of titanium alloys. The numerical simulation of saw-tooth chip formation, however, is still not accurate, since most of these numerical simulation models are based on traditional finite element method, which have difficulties in handling extremely large deformation that always occurs in the cutting process. Furthermore, these models adopt the Johnson-Cook damage constitutive law that is implemented in commercial codes such as ABAQUS (R) and LS-DYNA (R) to describe the dynamic mechanical properties of material, but Johnson-Cook damage constitutive law cannot account for the material of behavior due to strain softening and the dynamic recrystallization mechanism that occurs in the cutting process of Ti-6Al-4. Therefore, this work introduces a material constitutive model named hyperbolic tangent (TANH) and an improved smooth particle hydrodynamics method, and then develops an improved cutting model for Ti-6Al-4V titanium alloy through our in-house code to predict saw-tooth chip morphology and cutting forces. When compared to the experiments and Johnson-Cook damage model, the improved cutting model better explains and predicts the shear localized saw-tooth chip deformation as well as cutting forces.