【作者】 毕运波；

【导师】 柯映林；

【作者基本信息】 浙江大学 ， 机械制造及其自动化， 2007， 博士

【摘要】 整体结构件的数控加工变形是航空制造技术所面对的最突出问题之一，严重地阻碍了航空制造业的发展。因此，实现航空整体结构件数控加工变形的预测和控制具有重大的理论意义和工程应用价值。本文以加工变形预测为目标，采用理论分析、力学建模、有限元模拟和实验验证等手段，对航空整体结构件铣削加工过程物理建模与仿真关键技术进行了深入研究。第一章阐述了论文研究的背景和意义，分别总结了切削加工过程物理仿真和航空整体结构件加工变形的国内外研究现状，提出了本文的研究目标、意义、内容和总体框架。第二章在铣削加工机理理论分析的基础上，将复杂的铣削加工过程等效简化为基本的直角／斜角切削过程的组合。进而，通过正交直齿铣削实验，建立了硬质合金刀具切削加工航空铝合金7050-T7451过程中切削基本量与切削参数之间的经验公式，为后续铣削力和铣削热建模提供基本输入参数。第三章基于刀齿微元化思想，建立了铣削力预报机械力学模型和统一力学模型。通过铣削力实验，对比研究了两种铣削力模型的预报精度和各自的优缺点，并间接验证了第二章所建立的切削基本量经验模型的正确性。第四章在铣削加工热力学模型简化的基础上，分别针对直齿立铣加工和螺旋齿立铣加工，研究了热源强度解析计算、热载荷离散与动态施加等关键技术，建立了基于给定热源法的工件铣削温度场三维有限元模型，模拟得到单齿进给切削过程中工件温度场的动态变化过程。第五章着眼于航空整体结构件数控铣削加工全过程动态物理仿真，架构和开发了数控铣削加工物理仿真原型系统，并深入研究了刀位轨迹文件解析、材料去除、动态铣削载荷施加、网格自适应及动态网格数据维护、接力计算方案等有限元建模与仿真过程自动化关键技术。第六章借助数控铣削加工物理仿真原型系统，针对典型航空结构件整体加工变形和局部加工变形问题，分别建立了铣削加工过程有限元模型，预测了零件的加工变形，并通过实验验证了本文所采用的铣削加工全过程有限元建模策略的正确性和有效性。第七章对全文的研究工作进行了总结，并对有待进一步研究的内容进行了展望。更多还原

【Abstract】 The distortion of monolithic components due to CNC machining is one of the most striking problems that aeronautical manufacturing technology has to face up to, and hinders the development of the aeronautical industry seriously. So, it has greatly academic and engineering value to predict and manipulate machining distortion of aeronautical monolithic components. Aim to predict machining distortion, key techniques of physical modeling and simulation in the milling process of aeronautical monolithic components are studied on deeply by using theoretic analysis, mechanics modeling, finite element simulation and experiments verification.In chapter 1, the background and significance of this dissertation are introduced firstly. Then, the state of the art in the research of physical simulation in cutting process and machining distortion of the aeronautical monolithic components at home and abroad is summarized. Finally, the research target, contents and overall frame structure of this dissertation are shown.In chapter 2, based on theoretic analysis of milling mechanism, complex milling process can be equivalently simplified as combination of fundamental orthogonal/oblique cutting process. Furthermore, through orthogonal straight-tooth milling experiments, empirical equations are established between fundamental cutting variables and cutting parameters when cutting is processed between carbide cutting tool and aeronautical aluminum ally 7050-T7451. The empirical equation is used as basic input variables in the following milling force model and milling temperature model.In chapter 3, by cutting edge discretization, mechanistic approach and unified mechanics of cutting approach are used to set up milling force model separately. Then, by milling force experiment, the prediction precision and relative merits of these two models are analyzed, and the validity of empirical equations established in chapter 2 is verified.In chapter 4, through the simplicity of heat transfer model, investigation of key techniques, such as analytical calculation of heat flux, thermal load discretization and dynamic enforcement etc. are carried out respectively for straight- and helical-tooth milling process. With given heat flux, a three dimensional finite element model is proposed to simulate the distribution of temperature field in the workpiece.In chapter 5, a prototype of physical simulation system is developed to simulate the whole NC milling process of aeronautical monolithic component. The key problems concerned with the finite element modeling and automation of simulating process, such as tool-path file discretization, material removal, dynamic load enforcement, adaptive mesh generation and dynamic mesh data management, restart analysis etc. are studied deeply.In chapter 6, with the help of the physical simulation system, two finite element models of milling process, corresponding to the whole- and local machining distortion prediction of typical aerospace components, are proposed respectively, and the distortion is predicted. By experiment verification, it can be concluded that the finite element modeling strategy of whole milling process proposed in this dissertation is correct and valid.In chapter 7, systematical summary for the whole work in this dissertation is given, and the future work is discussed.更多还原