The Research And Implement Of Quadrilateral Mesh Generation Algorithm With The Feature Constraint

With the rapid development of computer and information technology, mesh technique has been successfully implemented on complicated numerical analytics and simulation in engineering fields, such as computational mechanics, hydrodynamics, finite element analysis. It becomes a powerful method of CAE analysis of sheet forming.This thesis contains the research and comparison of surface meshing technique and analyzes the principle and strengths and drawbacks of the commonly used algorithms such as Mapping, Topology Decomposition, Grid-based, Mesh Generation Scheme for Arbitrary Planar Domains and Geometry Decomposition, etc. It studies the quadrilateral mesh generation algorithm with feature constraint based on the above-mentioned research, which emphasizes on:(1) Research on quadrilateral mesh generation—Paving, which is mainly about nodes classification,quadrilateral mesh production,collision detection and grid optimization algorithm.(2) Quadrilateral mesh generation algorithm with feature constraint which is classified to point-restrict and line-restrict.For point-restrict, two kinds of algorithms are offered: pretreatment and real-time treatment. The pretreatment algorithm produces four quadrilateral elements with the piont-restrict and forms a unit-node loop. The real-time treatment is to test whether the point-restrict could meet the requirements of being nodes during the meshing process.For line-restrict, analyze and research on the intersection of the line-restricts and boundaries, and then discretize them to node-loop. Adopt combination method or one by one dealing method to process the node-loop, finally produce a loop of elements to every node-loop.Based on the research above, C/C++ language is adopted to implement the quadrilateral mesh generation with inner specific restriction algorithm, which has been successfully applied to the CAE software of sheet forming. This method is steady and reliable and the speed of meshing is fast. It can also improve the quality of elements of some regions without decreasing the quality of the whole elements.