Analysis And Simulations Of Residual Stresses In Machined Layer For High Speed Machining

The research of HSM mechanism, which is the theoretical fundamental of high-speed Machining (HSM), is critical for application and development of HSM technology. Surface quality, an important research content of HSM mechanism, is judged by residual stresses. Residual stresses in machined layer for HSM impact the working performance and fatigue strength of parts. Also, they are major affecting factors of defects such as deformation and crack. As a result, correct prediction of residual stresses in machining process has great theoretical significance and practical values.The theory of residual stresses in machined layer involves many cross subjects, such as mechanical manufacture, elastic-plastic mechanics, finite element method and etc. In view of the complex nature of problem, a method including experiments, theoretical modeling and computer simulating is proposed in this dissertation. Then, beginning with the metal cutting principle, deep theoretical researches and numerical simulations of residual stresses in HSM are carried out, and a predicting model is established. This is an important fundamental subject to promoting HSM technology development and application, which has a very important theoretical and practical significance to exploit HSM potential energy further.In this paper, firstly, the generation mechanism of residual stresses for machining is analyzed, the analytical model for the formation mechanisms of machined layer is established, and a thermo-mechanical coupling equation for the third deformation zone is constructed. Secondly, the distribution of residual stresses on machined layer and effects of machining parameters and tool geometry on residual stresses are studied, by the use of FEM procedure. Thirdly, experiments of high speed milling and residual stresses measurement are carried out in order to study the distribution of residual stresses and to verify the availability of FEM models. At last, a mathematical model of relationship between residual stress and affecting factors is promoted.