High-Speed Cutting Numerical Simulation Based On BCJ Constitutive Model

The high-speed machining technology has become one of the most important Manufacturing methods in large-scale production. Its technical characteristics are high grinding efficiency and high quality of machining surface which even reaches the level of grinding. So it is widely applied in the aerospace industry, and it plays a very important role in aeronautical aluminum alloys thin-walled monolithic components manufacturing. The finite element simulation technology is an important way in research of high-speed cutting process, but at present some emperical or semi-emperical constitutive models are widely used in numerical simulations of high-speed cutting. These constitutive models can't accurately describe materials'complex deformation behaviors during high-speed cutting process. To select more suitable constitutive model to describe materials'deformation behaviors in the cutting process for numerical simulation of high-speed cutting process is of great importance.This article which is based on BCJ constitutive model develops a method to embed BCJ constitutive model into a user subroutine to define materials'mechanical behaviors known as VUMAT secondary development in the universal finite element ABAQUS software platform, and establishes the two-dimensional orthogonal high-speed cutting finite element model to realize the aluminum alloys high-speed cutting process numerical analysis with high precision.1. Development of BCJ constitutive model embedded into ABAQUS VUMATIn the process of high speed cutting, materials'deformation behaviors are very complex. In order to realize more accurate descriptions of the dynamic performance of materials, this article introduced BCJ constitutive model based on the dynamics of dislocation. This arcticle expounded features and advantages of the BCJ constitutive model in comparison with other emperical or semi-emperical constitutive models, completed BCJ constitutive model VUMAT algorithm research and program realization, and also BCJ constitutive model user subroutines validation based on ABAQUS platform. Uniaxial tension test process simulation results showed that the embedded BCJ constitutive model user subroutines are correct.2. Adaptive mesh modeling method for high-speed cutting numerical simulationThis article discussed key technical issues of thermo-mechanical numerical simulation for high-speed cutting process, including scraps separation, heat problems in cutting production and adaptive meshing issues. In adaptive mesh modeling, combining the specific circumstances of aluminium alloys in high-speed cutting process, this article studied two kinds of modeling method, including Lagrange-Euler (ALE) and separation line (FZA) methods, and completed the aluminum alloys high-speed cutting process simulation using the two-dimensional orthogonal right-angle cutting model. These two kinds of mesh modeling methods'predictions of cutting heat and cutting force are very similar, but were very different in the forecasting of chip morphology. In FZA method chips were significantly jagged with sawtooth, and in ALE method chips were of continuous form. And aluminum alloys chips micrograph showed that the FZA method was more accurate in the prediction of chip morphology.3. Numerical simulation of aluminum alloys high-speed cutting process based on BCJ constitutive modelAccording to the complexity of the constitutive equation BCJ materials parameters and their characteristics, this article established a method using Matlab optimation toolbox to gain these material parameters. Then this article completed aluminium alloys high-speed cutting process simulations based on JC constitutive model and BCJ constitutive model. Combining 7075-T651 aluminum alloys cutting experiment, this paper analysed BCJ constitutive model's advantages in high-speed cutting numerical simulations. Compared with JC constitutive model, BCJ constitutive model predicted equivalent stress, cutting force and temperature more accurately. BCJ constitutive model can realize high speed cutting process calculation with more precision.This paper has established a platform of high-speed cutting numerical simulation and has realized high accurate calculation of high-speed cutting. Thus this pape provides the necessary technical means for aluminum alloys high-speed cutting process research.