Reasons for the tubesheet deformation of heat exchanger were analyzed in detail , which were mainly machining deformation and the deformation occurring during connection . processes for preventing the formation of tubesheet were proposed 详细分析了换热器中管板变形的原因,主要是管板的加工变形及加工时产生的变形,提出了防止管板变形的工艺对策。
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 第一章阐述了论文研究的背景和意义,总结了航空整体结构件数控加工变形的国内外研究现状,提出了本论文的研究内容和总体框架。
The reason that slightness shaft part is bended by turning is analyzed in the mechanics , design of radial move system & tool desk in the automatism cnc lathe is advanced , the design has solved the problem of that slightness shaft part is bended by turning with the tool machine structure 摘要从力学角度分析细长轴类零件车削加工变形原因，提出细长轴数控车床径向进给系统和刀台一体化设计方案，解决由于机床结构的原因所造成的细长轴类零件车削加工变形问题。
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 本文采用有限元模拟与试验研究相结合的方法,对航空多框整体结构件的铣削加工变形机理、预测方法以及变化规律开展了深入的研究,为该类结构件加工变形的控制奠定了基础。
Finally , the technic route for the research of milling distortion is proposed . in chapter 4 , the effect of tool path and clamping schemes on residual stresses as well as machining distortion are analyzed by using three - dimensional elastic - plastic fem ( finite element method ) . the distortion variation tendency under four typical tool paths , the pressing - plate clamping and stretched fixation is obtained respectively 第四章基于上述理论基础,利用三维弹塑性有限元技术分析了走刀路径和装夹方案对铣削加工残余应力分布和变形的影响,得到了四种典型的走刀路径以及压板式装夹和拉伸装夹对加工变形的影响趋势。
Machining deformation of aircraft monolithic component is simulated by finite element method ( fem ) and validated by experiment . the initial residual stress in pre - stretched plate is generated by simulating quenching and stretching processes . with a single tool - tooth milling process fem , the machining loads in monolithic component material removing is obtained . restart - calculation is put forward to complete the whole simulation of machining process . to verify the fem result , an experiment is carried out . the deformation distribution of the monolithic component resulting from fem shows a good agreement with the experiment result , which indicates that the key technologies presented in the paper are practicable and can be used to simulate the milling process of monolithic component to predict its deformation . lengthy and expensive trial and error experiment process can be avoided 在模拟淬火、拉伸过程获得含有初始残余应力的预拉伸板材以及模拟单齿切削过程获得切削载荷的基础上,提出并采用接力算法,对一航空整体结构件的材料铣削过程进行有限元仿真,同时进行了试验研究.结果表明,有限元模拟的整体结构件的变形与试验具有一致性,从而证明提出的整体结构件加工仿真关键技术的可行性,避免了为研究加工变形而进行的繁琐的试错法
Therefore , a base is provided for studying the effect of milling force on the machining distortion . in chapter 3 , according to the milling characteristics of the monolithic multi - frame components , the mechanics basis is discussed . after that , mechanical description and the 3 - d modeling rules are given , and the finite element model of the milling distortion of the multi - frame components is established 第三章结合航空多框结构件铣削加工的特点,对采用有限元技术研究铣削加工变形的力学基础进行了探讨,给出了航空多框结构件铣削加工过程的力学描述和三维有限元建模原则,建立了多框体铣削加工变形的有限元分析模型,提出了铣削加工变形研究的技术路线。
Thirdly , the delayed ownership reservation is a manifestation of the trend from the field of consumption to the field of industry and business ; and also he expounds on the buyer how to protect his creditor ' s rights when the buyer in a business - broker or manufacturer and the selling goods are re - sold in order to make profits or processed 第三，延长的保留所有权是保留所有权买卖制度由消费领域向工商业领域拓展趋势的体现，研究了当买受人为中间商或制造商时，保留所有权的出卖物品被转售获利或加工变形时，出卖人如何保全自己未得清偿的价金债权。
In chapter 2 , based on the status analysis on the research of milling force , its characteristic is studied for the aero - material of aluminum alloy 7075 - t7351 , and the empirical model is established by using the regression - orthogonal experimental method where the factor number is five and the standard number is four 第二章在总结国内外铣削力研究现状的基础上,采用多因素正交试验研究了航空铝合金7075 - t7351的铣削力学特性,建立了该材料的铣削力经验模型,为研究切削力对加工变形的影响提供了依据。
Based on analyzing the structure characteristic , the process difficulty and the original processes , the author puts forward the new optimization ways of the technology and make the technology rules . the article also discussed the research about the control of the casing parts " distortions and put forward new optimization technology that can effectively control the distortions 论文在充分分析机匣结构特点、工艺难点和原机匣制造工艺的基础上，提出了新的优化工艺路线，制定了新的工艺规程；对加匣加工变形的问题从工序调整等角度进行了研究，提出了变形控制方案。
