大型整体结构件铣削加工的变形研究

【作者】 苗勇；

【导师】 李迎；

【作者基本信息】 南京理工大学 ， 机械电子工程， 2012， 硕士

【摘要】 《国家中长期科研发展规划》将先进制造技术的未来发展方向明确为信息化、绿色化和极端化。本文运用理论研究和有限元仿真相结合的方法,对大型整体结构件的铣削加工变形进行了分析,分别研究了残余应力对整体结构件加工变形的影响,大型矩形薄板在重力作用下任意点支撑的变形情况,大型整体结构件铣削加工的变形预测。本文第一章阐述了论文研究的背景和意义,对大型整体结构件的变形特点及变形原因进行了分析,并详述了国内外研究现状,最后给出了本文的研究内容。第二章在对剥层法研究总结的基础上,概括出残余应力和变形挠度的计算通用公式,并通过编制的通用程序研究了其独立自变量(工件的初始残余应力、工件尺寸)对变形量的影响。第三章将基于重傅里叶级数和叠加法的小挠度薄板变形理论应用于大型整体结构件任意点支撑的变形研究,并结合有限方法,建立了大型矩形薄板在重力作用下任意点支撑的研究模型。重点解决以下问题：1)基于所建立的研究模型研究了相关参数对变形量的影响；2)建立了工件尺寸、材料以及支撑点的位置与工件变形的关系；3)建立了工件尺寸、材料以及支撑点的数目与支撑点的最佳支撑位置的关系；4)基于小挠度变形理论并结合有限元模型,对矩形薄板在柔性支撑时的间距选择给出建议；5)针对任意曲面的支撑情况,在对相关文献研究总结的基础上,提出了曲面支撑的一般思路并进行了参数化建模。并且,上述所有问题均编制了相关程序。第四章区别于以往的接力计算的铣削仿真模型,建立了铣刀与工件直接作用的铣削仿真模型,首先研究了常见的四种加工路径(外环形,内环形,“之”字形和并进形)对大型整体结构件铣削加工变形的影响,并基于上述模型研究了重力和支撑点对工件铣削加工变形量的影响。最后,基于最优加工路径,以三框和六框整体结构件为对象,研究了隔框件的铣削顺序对大型隔框类整体结构件加工变形的影响。第五章对整篇论文进行了总结和展望。更多还原

【Abstract】 State plans for medium and long-term development thinks the direction of advanced manufacturing technologies in future as informationization, green, extreme. The research uses the method of theoretical studies combined with finite element emulation. The analysis of the machining distortion of the large monolithic components was finished in this paper. It is studied that the effects of initial residual stress on machining deformation, the deformation of the big rectangular thin plate supported by points under gravity, the predict of the machining distortion of the large monolithic components.The first chapter expatiates the correlative background and significance of this thesis. The deformation characteristics and cause of the large monolithic components are studied. It details the situations both in China and abroad. Finally, it states the research topic.The second chapter studied and summarized layer-stripping, summarized the general formula of residual stress and deformation, studied the effects of the related variables on machining deformation by the general program.The third chapter applied the deforming theory of small deflection based on two-dimensional Fourier series and superposition method to the machining distortion of the large monolithic components, linked to the finite element method, established the model of the big rectangular thin plate supported by points under gravity. It priorities to address the following issues:1) The effects of the related variables on machining deformation is studied based on the established model.2) Establish the relationship between the dimensions and material of workpiece as well as the location of the support points and the deformation of the workpiece; 3) Establish the relationship between the dimensions and material of workpiece as well as the number of the support points and the best location of support point;4) Based on the theory of small deflection combined with the finite element method, gives advice about the span of supports;5) In view of the support situation of all curve surfaces, advances the way to the support of all curve surfaces on the base of research on the related literature.The fourth:The simulation model of the milling process was built, unlike previous the simulation model of the restarting analysis. The effects of the four most common processing path(ring from inside to outside, ring from outside to inside, abreast, zigzag) on machining deformation was studied. Base on the model, It is studied that the effects of gravity and supported points on machining deformation. The monolithic components usually have many frames. This paper takes a monolithic component with three frames and six frames as research subject. The effects of the milling machining sequences on machining deformation was studied.The fifth:Finally it summarizes the whole research work as well as the prospect of the project, and points out some features that need improved.更多还原