Research On Control Residual Stresses Mannel Of Aeronautic Frame Structure In The Milling

The machining distortion of monolithic components is one of the most striking problems in aviation manufacturing industry and hinders the development of the aeronautical industry seriously. It has important value to investigate the effect factors of machining distortion and methods for reducing or avoiding distortion.Six chapters are included in this dissertation, and the main work is as follows.In chapter 1, the background and significance of this research is introduced firstly. Then, the state of the art in the research of machining distortion of the monolithic component is summarized. Finally, the main contents and frame structure of this dissertation are shown.In chapter 2 and 3, based on the theory of cutting deformation of Aerospace monolithic components, from three dimensional cutting principles, the characteristics of machining distortion,and the key modeling techniques of monolithic components for the simulation, a method combining theoretical analysis with Finite element calculation and experiment is adopted in this dissertation to study the distortion prediction. The key modeling techniques of the machining distortion simulation for the milling process of monolithic components have been investigated, which include the simplification of geometrical model, simplification of cutting layer and the application of cutting loads.In chapter 4, by using finite element simulation and experiments, a deep study is carried out on the mechanism, the prediction method and the variation tendency of the milling distortion. The work in this dissertation can provide a basis for the distortion control of the monolithic multi-frame components. The effect of tool path and machining sequence on residual stresses as well as machining distortion are analyzed by using three-dimensional elastic-plastic FEM(Finite Element Method). The distortion variation tendency on milling under four typical tool paths, machining sequence is obtained respectively.In chapter 5, small dimension parts was machined and its deformation was measured on a coordinate measuring machine to comparing the simulation results and the real measurement in the distortion, the proposed model is proved to be effective.In chapter 6, systematical summary for the whole work in this dissertation is given, and future work is discussed. Author:Ke lieqiang(Material Science) Supervised by:Prof.Wang litao...