Numerical Analysis Of Large Thin-walled Parts’ Deformation In Milling Process

Large thin-walled parts play a decisive role in industries such as aerospace, nuclear, petrochemical, shipbuilding, military and so on. For reasons of low stiffness, poor material machinability, there usually is large deformation during the milling process, which not only affects the production efficiency, but also greatly reduces the machining accuracy. Researches on its processing deformation are of great significance for the improvement of manufacturing precision.In this dissertation, the mathematical model and simulation method of the milling process are studied systematically. Based on the mathematical model of the milling process, including plasticity theory of metal materials, stainless steel mathematical model and heat by plastic strain model, some key techniques including the setup of material model and coupled thermal-stress model, the chip separation criteria, the material failure criteria, friction definition at the tool/workpiece interface are further discussed. Through the force and heat analysis, the feasibility of the model was validated. The milling process of nozzle is simulated with the model and the deformation characteristics are analyzed, which provide a systematic method for the deformation study of large thin-walled parts.Static and dynamic characteristics of the nozzle vertical milling head is analyzed, and modal analysis is carried out through experiments, through which the main factors of the deformation are attained. The processing deformation of large thin-walled parts is studied from the viewpoint of fixture and milling machine, which has important guiding significance for actual production.This thesis is of great theoretical reference value and practical significance for the machining of nozzle in Xi’an Space Engine Factory.