Study On Application And Constitutive Model Construction Of Anisotropic Aviation Aluminum Alloy

As the preferred material for the main bearing components of modern aerospace components,the different rolling,pre-stretching and other forming processes of the aviation aluminum alloy lead to obvious anisotropic of its mechanical properties.Under the local deformation condition of high strain rate,large strain and high temperature in high speed cutting,it is more difficult to construct the constitutive model which can accurately reflect the high speed cutting state.It will limit the mastery of mechanical properties and deformation mechanism of materials under these conditions,and the development of cutting simulation deformation process.The research material is aviation aluminum alloy 7050-T7451 pre-stretched rolled sheet,with the theoretical analysis,experiments and numerical simulations,the dynamic mechanical properties under different forming directions/angles were analyzed,the angle function was introduced to characterize anisotropic,and the constitutive model for high-speed cutting with directional effect was constructed.Based on the constitutive model,the high-speed cutting simulation model under anisotropy was established,the relationship between cutting parameters-anisotropic-cutting performance was revealed,and the high-speed cutting process was optimized.The quasi-static loading experiments,dynamic impact shear experiments and static/dynamic mechanical properties analysis of the material under different impact loading directions were carried out by selecting the most representative prefabricated specimens with typical forming directions(rolling direction RD,transverse direction TD and normal direction ND).Considering the influence of material forming direction,the JC constitutive model parameters including the strain rate sensitive function term under different impact loading directions were determined,respectively.The comparison of calculation results in different models verified the effective constitutive model under different impact loading directions.The dynamic impact shear experiments and high-speed orthogonal cutting experiments were carried out on specimens with 0°,30°,45°,60°,and 90° in TD-ND plane,where the anisotropy of mechanical properties was most significant.Based on Oxley orthogonal cutting theory,the variation of shear angle,cutting force and cutting temperature under differentcutting speeds and feed speeds were revealed.With the cutting reverse method,the anisotropic JC constitutive model for large deformation cutting was constructed by shear stress,shear strain,temperature and material dynamic mechanics data in the deformation zone of high-speed cutting.With the AdvantEdge FEM cutting finite element software,the anisotropic JC constitutive model parameters under large deformation conditions were applied to establish the high-speed orthogonal cutting simulation model under different conditions,and the mechanical-thermal coupling behavior in the cutting deformation zone was analyzed.The influence of anisotropic characteristics on the cutting performance of the material was studied by taking cutting force and specific energy as comparative parameters.The influence of anisotropic characteristics on the cutting performance of the material was studied,and the optimization process range of improving the cutting performance by using the anisotropic of the material was proposed.