轴承定位套热锻成形的EFGM分析及应用

发布时间：2018-10-16 17:19

【摘要】：锻造是目前常用的金属塑性成形手段之一,通过锻造,能有效优化微观组织结构,改善金属力学性能。但由于锻造过程中涉及到高温及金属大变形问题,分析过程比较复杂。特别是对于模锻技术来讲,依靠已有经验进行试模、修模是目前最常用的技术手段,效率低、废品率高。随着机械工业的不断发展,传统的模锻工艺更难以满足不断提高的产量及品质要求。为了解决此问题,国内外专家学者提出对模锻过程进行模拟仿真的想法,试图发现并解决部分在试模过程中不可预见的问题。随着不断发展的模锻仿真技术,传统的有限元法由于网格的束缚及算法的限制,在面对一些比较复杂的塑性成形问题时,难以得出准确结果。对此,专家学者提出了用不局限于网格的无网格法进行金属塑性成形的仿真分析。本文在对国内外专家学者研究成果进行总结梳理后,对无网格理论进行了进一步研究,并将EFGM应用到解决某集团锻造厂轴承定位套锻件锻造过程中局部填充不足的问题中,以期找到导致其产生缺陷的原因,并对模具磨损情况进行分析与优化,为提高产品质量、改善锻造工艺等奠定了理论基础。主要研究内容如下:首先,对无网格法及其在金属塑性成形领域的研究现状及应用前景进行了分析,结合生产实际确定研究对象;其次,通过移动最小二乘近似原理及位移边界条件处理两个方面对无网格伽辽金法进行了研究。用悬臂梁弯曲和拉伸的数值算例进行了简单的计算和验证,确定了 EFGM为本文主要研究方法的合理性。再次,对金属刚塑性成形基本理论进行研究,说明了速度场近似及刚度方程基本原理,总结了算法流程,并建立了三维刚塑性EFGM模型。通过法兰盘热锻过程的实验与仿真,验证了三维刚塑性EFGM分析模型的正确性。最后,通过对轴承定位套毛坯热锻成形过程的实验与仿真,找出导致其出现局部填充不足缺陷的真正原因,提出改进方案,并对其热锻成形过程中的模具磨损情况进行分析与优化。
[Abstract]:Forging is one of the commonly used metal forming methods. Forging can effectively optimize the microstructure and improve the mechanical properties of metals. However, due to the high temperature and large metal deformation in forging process, the analysis process is complicated. Especially for die forging technology, die repair is the most commonly used technical means, with low efficiency and high scrap rate. With the continuous development of mechanical industry, the traditional die forging process is more difficult to meet the increasing production and quality requirements. In order to solve this problem, experts and scholars at home and abroad put forward the idea of simulating the die forging process, trying to find and solve some unforeseen problems in the process of die test. With the continuous development of die forging simulation technology, the traditional finite element method is difficult to obtain accurate results in the face of some complicated plastic forming problems because of the restraint of mesh and the limitation of algorithm. In this paper, a meshless method, which is not limited to meshes, is proposed to simulate and analyze metal plastic forming. After summing up the research results of experts and scholars at home and abroad, this paper further studies the meshless theory, and applies EFGM to solve the problem of insufficient partial filling in the forging process of bearing positioning sleeve forgings in a certain group forging factory. It is expected to find out the causes of the defects and to analyze and optimize the wear of the die, which lays a theoretical foundation for improving the quality of products and the forging process. The main research contents are as follows: firstly, the research status and application prospect of meshless method in metal plastic forming field are analyzed, and the research object is determined according to the production practice. The meshless Galerkin method is studied by moving least square approximation principle and displacement boundary condition processing. The numerical examples of cantilever beam bending and stretching are used for simple calculation and verification, and the rationality of EFGM as the main research method in this paper is determined. Thirdly, the basic theory of metal rigid-plastic forming is studied, the basic principle of velocity field approximation and stiffness equation is explained, the algorithm flow is summarized, and the three-dimensional rigid-plastic EFGM model is established. The correctness of 3D rigid-plastic EFGM analysis model is verified by experiment and simulation of hot forging process of flange. Finally, through the experiment and simulation of the hot forging process of the bearing positioning sleeve blank, the real cause of the defect of partial filling is found out, and the improvement scheme is put forward. The die wear in hot forging process is analyzed and optimized.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG316

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