| The high speed cutting process of metals is a complex thermodynamic coupling problem spanning over multidisciplinary fields of mechanics, mechanical engineering and materials science, which involves a series of dynamic phenomena like large elastic-plastic deformation, high temperature, high strain rate, failure fracture, strong friction, and so on. So it is hard to make a breakthrough by using traditional theoretical analysis. However, with the rapid development of computer technology, finite element (FE) method has become the most important way to study the process of high speed cutting. In this thesis, a2-D orthogonal cutting model is established to simulate the high speed cutting process of titanium alloy Ti6A14V based on finite element software platform ABAQUS/Explicit. Main influence factors for FE simulation are analyzed, such as constitutive model, failure criterion, friction law and mesh generation.In commercial FE software ABAQUS, the available constitutive relation of metals in material library is somewhat limited for high speed cutting process, which can not satisfy related research requirements. Based on the theory of stress compensation updating algorithm, we introduce the G-Z model into ABAQUS/Explicit through the explicit user material subroutine (VUMAT), and simulate the high speed cutting process of titanium alloy Ti6A14V. And then the results of Mises stress, equivalent plastic strain and temperature distribution are analyzed respectively. The chip morphology, cutting force, surface residual stress of workpiece are compared with experimental results and those obtained by existing J-C model. It is proved that the G-Z model is reliable for describing large deformation and high strain rate problems. By applying the G-Z constitutive model in the numerical simulation of Ti6A14V high speed cutting, an effective improvement on the FE computational method of metal high speed cutting process has been realized. |
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