Research On Non-uniform Grid Generation Of Finite Difference

Grid technology plays an important part in the casting CAE pre-treatment technology. Grid division is compsed of uniform grid and non-uniform grid. Uniform grid is more convenient, as long as the direction for the use of grid spacing can be fixed; but inadequate for those complex componeets, there will be a serious distortion by using the uniform grid division because uniform grid division is not easy given a fixed mesh step ( grid spacing).,sometimes there may be a lose of the characteristic information which will take a dramatic change; in order to ensure that the characteristics of details without losing of information and to adopt the entire scope of the engine used in the complex region as the characteristic length mesh step then that is bound to lead to a large amount of data redundancy. How to resolve this problem is an important factor which has a great impact on subdivision quality.Based on CASTSoft software-pakage developed by the University of North Foundry Engineering Research Center in this paper, pre-processing software for finite difference uniform grid research and analysis , on the basis of principle of Grid divided , through analysis the STL file of data and data processing then obtain each direction Slitting surface that has a diffrence distance between the parallel surfaces, propose an algorithm of finite difference non-uniform grid division. Finally elaborate the distinction between the non-uniform grid division and uniform grid and an effective solution to slove special occasion in the subdivision such as holes in STL files, slitting surface through the point of a small triangle and cutting line through the line to the apex of polygon domain.Besides, when the STL file is of large-scale, the model can be divided into a number of small integrated STL model,and then those models can be divided respectively.In this paper, a STL file of large-scale is divided into a number of small integrated STL model. The steps and algorithm of the generation and triangulation of section contour is detailed,and extreme occasion discussed classifiably.There is an effective method to ensure the intergrity of the process and the accuracy of the result.At the same time because the STL file is lack of films between the topology information,there will be a large number of redundant data , even many mistakes and flaws.The paper introduces the classification and the repair.Finally , this paper gives the a non-uniform grid dividing program and the the segmentation program and application examples using VC + + 6.0 development environment develpement.