The Simulation And Experimentation About Machining Distortion Of Hub Brake Cap Based On Residual Stress

The thin-wall structure with high machining accuracy are adopted in the keycomponents of the vehicle drive system to meet spatial constraint and special workcondition requirements, such as planet carrier, gear ring and hub brake cap. However,distortion is easily occurred in the machining process of these parts due to the residualstress. So the research on the influencing rules of residual stress on the machiningdistortion have critical significance. This thesis analyzes the impact of cuttingparameters on residual stress by means of theoretical analysis, finite elementsimulation and scientific experiment. Then the influence of the release of residualstress on machining distortion is studied, and the optimization of cutting parameters isdefined according to the analysis. The main research work includes the followingaspects:Firstly, the Johnson-Cook flow stress model of the hub brake cap material isestablished by experiment according the high strain, high strain rate and hightemperature characteristics of the cutting process. The material model is then used tobuild the machining induced residual stress theoretical model combined with thecutting force model proposed by Oxley and cutting temperature model proposed byKomanduri.Secondly, the influencing rules of the cutting parameters on machining inducedresidual stress in hub brake cap is studied by means of finite element simulation andexperiment methods. The finite element model of orthogonal cutting process isestablished using the software of ABAQUS. The different cutting parameters aresimulated to obtain the residual stress distribution along the depth into the workpieceand the influencing rules of different machining parameters on the distribution ofresidual stresses are analyzed. The cutting experiment on the bar blank made of thematerial of the hub brake cap is carried out using different cutting parameters. Theresidual stress on the machined surface is measured and the influencing rules ofcutting parameters on the distribution of residual stress are analyzed.Finally, the influencing rules of residual stress on the hub brake cap machiningdistortion are analyzed. The3D finite element model of the hub brake cap machiningprocess is build using ABAQUS software. The different cutting parameters aresimulated and the residual stress distribution is same as the result of experiment,which proves the validity of finite element simulation. The machining distortion caused by the release of the residual stress generated by different cutting parameters isanalyzed. At last, the optimal choice of the cutting parameters is established.