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题名: 钛合金复杂零件增材制造工艺的数值模拟
其他题名: The Process's Numerical Simulation of Titanium Alloy Complex parts Additive Manufacturing
作者: 王福雨
导师: 刘伟军 ; 赵吉宾
关键词: 增材制造 ; 工艺研究 ; 数值模拟 ; 热力耦合场 ; 多元回归分析
索取号: O241/W38/2015
页码: 123页
学位专业: 机械电子工程
学位类别: 博士
答辩日期: 2015-05-27
授予单位: 中国科学院沈阳自动化研究所
学位授予地点: 中国科学院沈阳自动化研究所
作者部门: 装备制造技术研究室
中文摘要: 金属增材制造是近年来在快速原型技术(Rapid Prototype,RP)的基础上不断发展和完善起来的一项新技术。金属增材制造技术利用计算机三维技术将3D模型分层切片,结合CNC数控技术和高能量激光束将金属粉末熔化并逐层累加形成实体零件。目前该技术已在航空、航天、医疗等领域有广泛的应用,在其他领域未来该技术必将得到更广阔的发展。本文以973激光快速成形项目为依托,研究影响金属增材制造的关键参数与成形温度、应力、成形质量的关系;以钛合金TC4为突破点,解决成形过程中变形开裂、成形表面不平整导致成形无法继续进行以及塌边等质量问题;实现金属零件的快速、低成本增材制造。本文采用实验与仿真相结合的的方法,综合分析关键成形参数对成形质量的影响。使用高温热像仪监测成形时的熔池温度;用小孔法和压痕法测残余应力;利用有限元软件MSC.Marc对增材制造过程进行仿真,得到瞬态温度场和应力场的演化规律,揭示了金属增材制造过程温度场与应力场的关系,总结了演化规律,达到项目的预期要求,实现金属材料增材制造过程从参数实验、模拟加工、试加工、检验检测到最后整体加工成形的全过程预测。本文主要的研究内容与成果如下:1、利用生死单元技术与移动高斯热源,通过有限元软件MSC.Marc实现TC4增材制造过程的试验样件模拟。模拟采用热力耦合求解方式进行,加快了求解速度;求解结果的温度与实测温度进行了对比,变化趋势相同,验证了模拟的正确性。从结果文件中提取出的温度场、温度梯度、热应力场和残余应力场的分布,便于总结规律,实现了对成形试件时间上和空间上的全面观测。2、在完成试件模拟的基础上开发了可视化参数设置系统,实现工艺参数、试件几何尺寸、材料物理参数、结果提取设置的直接输入,生成有限元前处理软件MSC.Mentat可以读取的过程文件,从而提高试件模拟的速度、易于实现成组模拟。该可视化人机对话系统大大缩短了建模的时间和对MSC.Mentat软件操作的要求,使研究人员可以把主要精力用于对不同参数模拟结果的分析中。3、提出了改善和抑制塌边的新扫描路径。提高了体积成形的输入功率,加快了增材制造速度、节省了时间;同时也提高了表面质量和表面平整度,使加工可以连续进行;保证了加工零件的尺寸,尤其对等截面柱状零件,截面尺寸基本一致。该扫描路径是大型零件增材制造顺利进行的有力保障。4、利用生死单元技术对钛合金增材制造过程进行热力耦合数值求解,得到顶层三个位置的残余应力。对关键参数与残余应力做多元回归分析,得到多元回归方程。通过有限元分析和实验验证了多元回归方程的正确性,证明多元回归方法是减少不同参数下成形件残余应力的预测与试验时间、对既定参数残余应力评估的有效方法。5、研究成形过程常见的转角与弯曲半径构成的复杂薄壁件零件的成形过程,得到不同转折角度、弯曲半径对成形质量的影响,并提出提高质量的方法。解释了制造中在转角与转弯处常见的质量通病,为完善加工工艺提供理论支持。6、提出了子区域模拟方法,解决了大型零件增材制造过程无法模拟或模拟时间长的技术现状。这是种新方法是将整体的模型按照成形区域进行分解,每个部分都可以进行单独的计算。可同时在不同的计算机上计算,也可在一台计算机上分别计算。在计算过程中不需要进行数据交换,当每个子区域完成计算后,将所需要的模拟结果提取出来后进行叠加得到整体的模拟结果。利用该方法已进行了整体叶盘零件的模拟,类似零件已进行了增材制造。
英文摘要: In recent years, metal additive manufacturing, continuing development and improvement, is a new technology based on the rapid prototyping technology. Metal additive manufacturing technology uses computer 3D model technology to slice the model. The parts are cumulated layer by layer, used matel powder combining with CNC numerical control technique and high energy laser bean. At present, the technology has been wide using in the aviation, aerospace, medical and other fields. And in the future, this technology will get a broader development in other fields. Based on 973 rapid prototyping, the relationship between the key paraments of matel additive manufacture and the forming temperature, stress and forming quality has been research. TC4 is a breakthrough point. The quality problem of the forming crack, edge collapse and uneven of surface in the forming process which would lead the forming process cannot continue has been solved. The matel parts have been rapid and low cost additive manufacturing. This article combines the experiment and simulation method. The key effects of forming parameters are analyzed comprehensive. The moltem pool of the matel additive manufacturing is supervised by high temperature thermal imager. The residual stress of the metal additive manufacturing parts is measured with small hol method. Using finite element software MSC. Marc for forming process simulation, I get the evolution law of transient temperature field and stress field, which law reveals the relationship of the temperature field and stress field metal additive manufacturing. I summarize the evolution rule, reach the expected requirements of the project, and achieve the additive manufacturing process from parameter experiment, simulation processing, try processing and inspection and testing to predicting of the whole forming process. In this article, the main research contents and results are as follows:1.Using life and death technology and gauss heat source, through the finite element software MSC. Marc, the TC4 additive manufacturing process of experimental samples had been simulated. The simulation speed is faster by thermo-mechanical coupling solving way. Compared with the results of the temperature and the measured temperature, the trend is the same, which verify the simulation is validity. Extracted the temperature field and residual stress field, temperature gradient and thermal stress field distribution from the result file, which are convenient to summarize regularity. The forming parts are observed comprehensively in time and space.2.The visual parameter setting system is developed on forming parts simulation. The system realized the process parameters, the size of the part’s geometry, the material physical parameters and the result set can be directly input. The system will generate the intermediate files. The finite element software MSC. Marc can read them, though the software can make the process simulation faster and in group. So the simulation time is greatly shorter and the requirement of the finite element operation is lower. The researchers can make their main energy on the analysis of the different parameters of the simulation results.3.The new scanning path, which can improve and control the edge collapse, has been put forward. The path increases the bulk forming input power, accelerates additive manufacturing speed, and saves the forming time. It improves the surface quality and roughness, which make the forming process to continue. The new scanning path guarantees the size of the part’s process, especially the equivalent section column parts. This method guarantees the large part formed smoothly by additive manufacturing.4.Using life and death finite element technology in titanium alloy additive manufacturing process with thermal mechanical coupling, after the simulation, get the residual stress of three top positions. The key parameters and the residual stress through the multiple regression analysis, multiple regression equation is obtained. The finite element analysis and the experiment prove the validity of the multiple regression equation, and the multivariate regression method is useful to reduce the time of the prediction and test for the residual stress under different parameters. The method is effective to the residual stress of the given parameters.5.The complicated thin-walled parts forming process of common angle and bending radius have been studied. The forming quality is influenced by the different twist angle and bending radius, and the method that how to improve the quality is put forward. The common quality faults of the different twist angle and bending radius have been explained. This study is theoretical support of improving the process.6.The subarea Simulation method is proposed,to solve the large parts additive manufacturing problems of the forming process Simulation and Simulation time too long status. The new approach is segmented the whole model to subarea, according to the region forming process. Each subarea can be calculated separately. The calculation can be on different computers at the same time, and also can be computed on the same computer. The result data of the calculation is not required to exchange, during the calculation. When the subarea calculation is finished, the whole simulation result is constituted bythe linear superposition of the subarea simulation results. The large parts have been simulated by this subarea simulation method, and the similar parts have been manufactured by additive manufacturing.
语种: 中文
产权排序: 1
内容类型: 学位论文
URI标识: http://ir.sia.cn/handle/173321/16768
Appears in Collections:装备制造技术研究室_学位论文

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