Study On Surface Residual Stress Of Milling Aluminum Alloy And Optimization Of Processing Parameters

At present,aluminum alloy has been widely used in construction,packaging,power electronics,aerospace engineering,nuclear power engineering,automobile industry,rail transit and other industries.It has high strength,fracture toughness,corrosion-resistant and fatigue resistance and so on.There are a lot of aluminium alloys,7075-T6 aluminium alloy is widely used in major aircraft construction components,for example,web,rib,leather,wing and rib,etc.However,during and after the processing of aircraft structural parts,there will be some process errors,such as tool transfer,machining deformation and so on.Among them,there are many factors causing machining deformation,so this paper takes the machining residual stress as the research point.According to this study,the research on the residual stress during milling of aluminum alloy is carried out by experiment,theory and FEM.Firstly,the milling force experiment,the internal initial residual stress experiment and three groups of milling residual stress experiment of 7075-T6 aluminum alloy are carried out.The experimental research laid the foundation for the analysis of the formation mechanism of the residual stress in subsequent machining processing,and then a finite element model of residual stress based on the milling process was established and verified.Secondly,based on the measurement of residual stress in the milling process,the 2D orthogonal cutting simulation of aluminum alloy using ABAQUS FEM,the forming mechanism of residual stress in cutting process is analysed..The resulting cutting force and cutting heat are the main sources of residual stress,the mechanical and thermal stress were built theoretically,and the effect of material cutting was analyzed,phase transformation on cutting residual stress is briefly analyzed.Then,with the support of Abaqus finite element software,the milling residual stress is solved by using two solvers Abaqus/Explicit and Abaqus/Implicit,and the secondary development of Abaqus is carried out.The interior residual stress of aluminum alloy 7075-T6 blank residual stress is given to the workpiece surface by SIGINI user subroutine.The residual stress of milling operations with the initial residual stress of the blank was solved.Finally,based on the finite element calculation model of milling residual stress,the cutting parameters are optimized by combining single factor with response surface method,and the influence of various process parameters on cutting residual stress in the cutting process is studied,and finally a set of optimal milling process parameters is selected.After that,three plug-ins for solving milling residual stress are developed,which can greatly improve the modeling efficiency of finite element model of milling residual stress.