【作者】 常素萍；

【导师】 李赞；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2004， 硕士

【摘要】 板料成形过程的有限元模拟能够对板料成形过程中的塑性变形、微观组织的变化和材料破坏机理进行有效的分析,优化和改善模具设计和工艺过程,缩短模具的设计和加工周期,降低生产成本并提高模具的加工质量,因此被广泛地应用于板料加工领域。论文根据板料成形有限元模拟的要求,对模拟的前置处理,有限元分析和后置处理的功能进行了分析,着重讨论了有限元前置处理系统的各个要素,前置处理系统的功能要求以及有限元分析对网格的基本要求。针对板料成形过程有限元模拟前处理中数据模型建立时出现的问题,分析了有限元前置处理中数据结构的处理。前置处理中的网格模型作为有限元模拟分析的前提,网格质量对计算结果的精度有很大的影响。论文介绍了网格模型建立的原则及网格划分技术,以STL文件格式为基础,建立板料成形有限元模拟的网格模型。论文主要针对有限元前置处理系统中网格模型的建立过程中出现的问题进行了分析研究,其中重点分析了STL文件中的复杂网格缺陷的修复。网格缺陷的存在影响后续的有限元计算,一般的有限元模拟软件只能对简单的缺陷进行手工修复。论文通过分析STL文件中一些典型网格拓扑结构缺陷的具体特征,提出了正常网格造型的判别准则和确定边界的算法,针对STL文件中网格造型的不同拓扑结构错误的自动识别和修复算法,实现对板料成形有限元模拟前置处理系统对网格模型的修复。更多还原

【Abstract】 Sheet metal forming simulation of FEA efficiently analyze the transforming of the sheet metal forming process and microstructure, and material destroy mechanism, optimize and improve the die design and manufacture process, shorten the time of designing and manufacturing, reduce manufacturing cost, and improve the manufacture quality of die, so it is applied extensively in sheet metal forming process.According to the requirements of finite element simulation of sheet forming, this paper analyzes the functions of pre-processor, simulation solver and post-processor of finite element simulation of sheet metal forming. The elements and the function requirements of preprocessing system and the requirement to mesh of FEA are mainly discussed. A method to deal with the date structure of the pre-processor is analyzed to solve theses problems existing in the process of designed and organized the data structure of the pre-processing system. Mesh modeling of pre-process is the base of the FE simulation of sheet metal forming, because the quality of mesh modeling has a great effect on result of FE simulation. This paper introduces the principles of the establishment of mesh modeling and the methods of mesh generation, and the mesh modeling of FEA was built up based on STL file format. In this paper, these problems existing in the structure of the mesh model in the pre-processing system are analyzed, and the method to repair the mesh modeling based on the STL file format is mainly discussed. Mesh drawbacks have great effect on the FEA of sheet metal forming and many FE simulation softwares just manually repair these simple drawbacks. The features of mesh drawback in STL file is analyzed. A criterion to judge the correct mesh model and a boundary discriminate algorithm is proposed. And automatically discrimination and repair algorithms for some typical mesh drawbacks are achieved for the pre-processing system of FE simulation of sheet metal forming.更多还原