基于AutoCAD的有限元前处理软件开发

【作者】 杜文辽；

【导师】 贾高顺；

【作者基本信息】 浙江工业大学 ， 2001， 硕士

【摘要】 本文主要研究基于AutoCAD平台，开发有限元前处理软件，实现绘图软件CAD和有限元前处理的无缝集成。使用ObjectARX开发系统，充分利用了面向对象C++语言的数据可封装性、可继承性及多态性的特点。软件开发的基本思路是从AutoCAD生成的几何模型（二维或三维）中提取数据，进行拓扑分析，将数据传递到网格剖分模块，实现网格自动剖分并以图形的方式显示剖分网格、约束以及边界信息，创建了一些具体的类，并定义这些类的属性和方法，实现有限元前处理的功能。 论文第一章首先介绍了有限元前处理技术的发展和现状，重点介绍了模型生成技术和有限元网格自动剖分技术的进展和前沿研究。论述了本文的研究背景、主要内容和目标。 论文的第二章介绍了AutoCAD图形数据库结构和ObjectARX开发方法。在分析AutoCAD图形数据库结构基础上，进一步介绍了对AutoCAD进行二次开发的常用方法，阐明了ObjectARX开发是最有前途的开发方法这一结论。文章分析了ObjectARX类库构成和派生新类的方法。 论文第三章讨论了在ObjectARX开发环境下，利用C++实现有限元前处理软件的开发。从几何模型着手，提出了从AutoCAD数据库中直接读取数据的思路，二维三维模型数据提取采取了不同的方法。提取出来的数据作为有限元网格剖分的必要准备，文章讨论了二维和三维问题有限元网格剖分映射法的实现以及剖分过程中相关信息的生成。利用面向对象的方法，构造了具体的网格类、单元类、节点类、载荷类等，并在网格剖分结束后以图形的方式显示剖分结果。本文改进了连续超限插值方法。在这一章还讨论了网格剖分过程中遇到的问题、解决办法以及一些具体处理技巧。 为了方便命令的执行和数据的输入，在第四章实现了界面的设计。开发了用于简化命令执行的菜单，利用MFC，配合AcUi、AdUi类库开发了具有和AutoCAD内部相同风格的输入对话框。 在第五章，运用设计的软件，列举了几个剖分实例。 最后，对论文进行了总结，并对未来的工作进行了展望。更多还原

【Abstract】 The thesis studies the development about the FEM pre-processing software which achieves the non-slot integration between drawing software CAD and FEM pre-processing, which is based upon the AutoCAD platform. it makes enough use of the characteristic of the object-oriented character of C++ including encapsulation, inheritance and polymorphism. The basic train of thought is that extracting data from the geometry model produced by AutoCAD (two-dimension or three-dimension), then carrying out topology, transferring data to mesh generation module, achieving mesh auto-generation and illustrating the mesh, adding boundary information. This paper builds several specific classes and defines both the attribute and methods, which achieve FEM pre-processing. Chapter 1 shows the development and actuality of FEM pre-processing in advance, and emphases the development and front study on modeling and FEM mesh auto-generation technology. It also discusses the research background, main content and aim. Chapter 2 introduces the structure of AutoCAD and the development method of ObjectARX. Based upon the analysis of AutoCAD structure, discusses the common method of re-exploitation of AutoCAD, and then comes to the conclusion that the ObjectARX has the greatest prospect. The thesis analyses the frame of ObjectARX class library and method of deriving new class. The next chapter discusses the development of FEM pre-processing by C++ under ObjectARX. Commencing from the geometry model, it gives the thought on extract data from the AutoCAD database and adopts different methods for 2D and 3D models. The data are preparation of FEM meshing. The paper discusses the achievement of FEM meshing in 2D arid 3D with mapping and the generation of relational information. The specific mesh class, the element class, the node class, the load class etc. are all set up by object-orient and the result is illustrated after mesh generation. The paper develops the method of transfinite interpolation. Problems, solution and some techniques encountered in the process of meshing are also discussed in this chapter. In order to make the command performance and the data input more convenient, in chapter 4, it provides a design of the interface. The menu simplii~iing commands performance is developed. The inputting dialog box with the same style as AutoCAD II ABSTRACT is developed by making use of MFC associating with AdUi and AcUi. Chapter 5 gives several examples. Finally, conclusions and prospects are given.更多还原