| Because of its large structure size,high material removal rate and thin wall,the distortion of the weak rigid structural parts in aeronautical is remarkable.The release of internal residual stress caused by material removal and the influence of surface residual stress during the machining are the main reasons for structural distortion.Therefore,it is significance for the prediction of simulation and the control of distortion by investigating the initial residual stress and surface residual stress.In this paper,the machining distortion is investigated through experimental research,analytical analysis and numerical simulation.The main contents are as follows:(1)The influence of initial internal stress on the residual stress is analyzed on the basis of the theory of thermal force coupling.The two-dimensional orthogonal cutting simulation and cutting test under the multi horizontal internal stress condition have been completed,and the surface residual stress distribution data under the multi horizontal internal stress are obtained.The influence of internal stress on the machining residual stress is mastered.(2)The initial stress and the machining stress coupled distribution on the surface of thin-walled parts are analyzed statistically.The numerical model of the coupled distribution is established,and the influence of the coupled stress on the distortion of the thin-walled parts is analyzed by simulation.It is significant influence on distortion of ultrathin-walled parts by coupled stress of high initial stress and machining residual stress.(3)Based on the physical equation of elastic mechanics,the relationship between the release of initial residual stress,the evolution of strain energy and the distortion is revealed.A numerical model of T type shrinkage parts has been established.According to the evolution of strain energy,the machining distortion of parts has been improved by optimizing the allowance distribution and processing path. |
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