Papers by Author: Zhi Ping Xu

Abstract: Johnson-Cook (JC) constitutive model is extensively used in the simulation of metal machining. There are several different sets of JC material constants for titanium alloy Ti6Al4V fitted by split-Hopkinson bar (SHPB) tests. However, few researches have been done to study their sensitivity on the behavior of cutting. In this work, four different sets of material constants were performed in a 2D numerical model to simulate the cutting process of titanium alloy Ti6Al4V. The effects of the four sets of material constants on the predicted cutting forces, chip morphology and temperature were studied. It is shown that all the considered process outputs are very sensitive to material constitutive constants. Some quantitive comparisons with experimental results reported in the literature were also made.

Abstract: In machining, the size effect is typically characterized by a non-linear increase in the specific cutting energy (or specific cutting force) as the uncut chip thickness is decreased. A finite element model of orthogonal micro-cutting was established to study the influence of tool edge radius on size effect when cutting 7050-T7451 aluminum alloy. Diamond cutting tool was used in the simulation. Specific cutting force and specific cutting energy are obtained through the simulation. The nonlinear scaling phenomenon is evident. The likely explanations for the size effect in small uncut chip thickness were discussed in this paper.