【作者】 牛宏建；

【导师】 张云鹏； 甘雨；

【作者基本信息】 西安理工大学 ， 材料加工工程， 2002， 硕士

【摘要】 本文对球墨铸铁件的凝固过程数值模拟软件进行了研究与开发，整套模拟软件由前处理网格自动剖分程序、球铁件模拟计算程序和后处理计算结果显示程序三部分组成。整套软件以Viusal C++作为开发工具在Windows环境下采用面向对象的方法设计，具有功能全面、显示速度快、界面友好、易于操作的特点。 前处理程序利用中、高档三维造型软件提供的图形数据接口STL格式文件，开发出了基于STL实体模型的网格自动剖分程序。剖分方法为：首先利用STL实体模型的连续性进行快速分层，求得每层的二维轮廓线，然后在二维切面上，按照区域填充的算法，将二维封闭轮廓线包围的区域填充为相应的材质属性。对于铸件-铸型的多材质系统，按照设定的顺序和材质属性依次剖分每个实体模型。为了满足对不同材质STL实体模型及其位置关系的观察，采用OpenGL技术实现了三维实体模型的图形显示。 模拟计算程序中采用了三维不等剖分且占用内存很小的离散方程系数存贮方法并在传热计算中直接引用，使模拟计算速度大幅度提高。采用一种基于热焓-温度关系的潜热处理方法，并采用符合球铁凝固特点的固相率-温度关系式，使球铁件凝固模拟中的潜热处理更为合理和简便。 后处理程序中，利用Windows提供的图形功能，实现了铸件三维网格剖分图形的显示，铸件的凝固动态显示和温度场的显示，并具有剖视、旋转及缩放等图形功能，使模拟的结果亘观化、形象化。 将所开发的模拟软件应用于实际生产的中等复杂球墨铸铁件的数值模拟中，结果表明该模拟软件是可靠的、有效的、具有一定的实用价值。更多还原

【Abstract】 In this thesis, a set of software was developed used for numerical simulation on solidification process of ductile iron castings. The software was made of three parts: the program of pre-processing used for auto-mesh generation, the simulation calculating program of ductile iron and the program of post-processing used for displaying simulation result. The software was developed with Visual C++ programming language and used object oriented programming technique based on PC windows system. The software was characterized by comprehensive functions, high display speed and easy manipulating.The pre-processing program took the advantage of graphic data interface STL file which generated from medium or top-grade CAD software, base on STL solid model the auto-mesh generation codes used for numerical simulation of casting solidification process were developed. The principle of the auto-mesh generation is: first of all, using STL solid model’s continuity to speed up the process of model’s cutting, and the contour lines of each layer were calculated. Secondly, on the cutting planes, according to area filling algorithm, the cells enveloped by contour lines were determined and given an according material number. For the casting-model system of various kind of material, according to this method, the STL solid models were treated one by one to carry out the mesh generation with predetermined order and material property. In order to meet the need of observing differ material STL solid models and it’s location relations, the OpenGL technology has been adopted and realized the 3-dimensional solid model’s display.In the simulation calculating program, a quite simple measure to store andThe research is supported by school youth scientific fundcall the coefficients in discrete equations was adopted, for the system unequally divided in three dimensional spaces, the measure made the CPU time for computing temperature field greatly reduced. The latent heat release process was perfectly simulated by using an exponential relationship between solid fraction and temperature.In the post-processing program, taking the advantage of windows GDI technology, the program can display casting’s 3-dimensional meshed graph, the casting solidification processing animation and the distribution of 3-dimensional temperature field. The program also includes general 3-dimensional graphic function such as cutting, rotation and zooms as to make the simulation resulting visualizing.The software has been applied to middle complex castings in real manufacture, the result indicated the software is reliable, effective and has certain practicable value.更多还原