Machining Deformation Prediction And Research Of Influence Factors For Large Thin-walled Workpiece

Large thin-walled structural parts have excellent features such as compact structure,saving materials and light weight,and can effectively reduce overall structure mass.In recent years,they have become more and more widely used in aerospace field.However,because of the feature of thin wall and low stiffness,thin-walled structural parts are highly susceptible to deformation during machining processing,due to the effects of initial residual stress,cutting forces,clamping and other factors,which seriously affects the use performance and precision stability of thin-walled parts.Therefore,making reasonable analysis and prediction of the machining deformation of large thin-walled structural parts,researching main influence factors of machining deformation and providing reference for proper deformation control measures do have important theoretical value and practical significance.Firstly,based on the numerical simulation technology of met al machining,this paper establishes thermal-mechanical coupled 2D cutting model and 3D milling machining model of aluminum alloy using ABAQUS software,obtains the variation regularities of cutting forces and cutting heat under different cutting parameter s,and analyzes the situation of the three-way milling forces,the stress field and the strain field.Then the finite element model of thin-walled cylindrical workpiece for solution and quenching process is established.The distribution of temperature field and heat stress field during heat treatment are obtained by simulation method.The initial residual stress field during the analysis of machining deformation is obtained.Then by coupling of initial residual stress,cutting forces,and clamping condition,this paper uses the element birth and death technique to simulate the material removal by ABAQUS software,writes subroutine in Fortran to control loads applying.Thus,the situation of residual stress and machining defo rmation of the thin-walled workpiece are obtained.Finally,based on the special fixture plan,the machining deformation s of thin-walled workpiece under different tightening blocks are obtained by finite element simulation,which proves that the fixture layout with 12 blocks is the most reasonable.The influence of different cutting parameters on machining deformation is studied as well,which provides the basis for the choice of cutting parameters.