用 AutoCAD 开发环境研制有限元平面问题的前处理系统

Researching the Pre process System of the Finite Elements Method Advanced Developing System Included in AutoCAD

本文提出了用矢量点乘及叉乘搜索极小封闭区域的算法，把每个极小封闭区域作为一个超单元，采用双线性插值方法，把每个超单元转化为局部坐标系下的规则正方形，按等分的方法对正方形进行网格的自动划分，同时记录局部坐标系下的结点及单元信息，然后又采用双线性插值的方法，把局部坐标系下的单元及结点信息转化为整体坐标系下的信息．约束、荷载及材料参数均采用交互方式输入，用户不需填写任何数据文件，做到真正的图数一体化．

An algorithm is presented to search the min closed region with the vectors dot product and cross product. Every min closed region is regarded as a superelement and every superelement is changed into a ruled square under the local coordinate system by double linear interpolation. While the ruled square is divided into equal element meshes automatically, the information of the nodes and elements is recorded at the same time. Then with double linear interpolation, the information of the nodes and elements under the local coordinate system are changed into that under the global coordinate system. According to the above method, a computing program is developed. As all the information of the constrain, load and properties of the material inputs interactively, users do not need to fill any data files.