Research On Residual Stress And Machining Deformation Of Aluminum Alloy Structural Parts

With the rapid development of the aviation industry,aircraft structural components have also been improved in the direction of large-scale and integrated,such as: casing,integral frame,ribs and so on.Due to the complicated structure and many thin-walled parts,these integral structural parts are prone to deformation during the cutting process and subsequent assembly and commissioning stages,which affects the machining accuracy and assembly performance.Aiming at the problem of machining deformation,this paper uses the combination of simulation and test,mainly studies the influence of residual stress and the tool path pattern on the deformation of aluminum alloy structural parts,and optimizes the milling parameters based on the surface residual stress.Firstly,the influence of different milling parameters on the surface residual stress of2024 aluminum alloy component was studied by finite element method.The orthogonal parameters and single factor test were used to optimize the milling parameters,and the empirical formula of machining residual stress was obtained.Milling tests were performed to measure surface residual stress.The results show that the experimental results are similar to the simulation results and the results calculated by the formula,which verifies the accuracy of the finite element model and the empirical formula.Secondly,it is difficult to carry out the finite element accurate simulation prediction for the machining deformation caused by the residual stress of the irregular structure.Based on the theory of elastic mechanics and the principle of linear superposition,this paper proposes a finite element prediction method for machining deformation that can simulate the actual cutting process.It can perform finite element simulation analysis according to the complex trajectory and based on the “precut” theory,a “contour-depth priority” tool path pattern was proposed.The simulation trials is conducted to verify the effectiveness of this tool path pattern to control the machining deformation.Finally,the machining deformation of the two-frame integral member was studied by finite element simulation and milling test.The initial residual stress of the blank,the residual stress caused by the processing,and the combined effects of these two influencing factors are considered.The results show that the initial residual stress is the main factor causing the deformation of the two-frame monolithic beam.The combined effect of the initial residual stress and the surface residual stress exacerbates the deformation.