High Quality Hexahedral Mesh Generation Based On Swept Volume Decomposition

In today’s world,increasingly fierce global competition has led to an ever-increasing demand for shortening product development cycles and reducing development costs.Since finite element analysis technology plays an important role in product development,and hexahedral mesh is an important input of finite element analysis,the automatic generation of high-quality hexahedral mesh has always been valued by both industry and academia.However,due to various reasons,the automatic generation of high-quality hexahedral meshes for complex solid models is still a recognized problem.In view of the problem that a lot of manual interaction is needed in order to generate high-quality hexahedral meshes for complex solid models,this dissertation studies on swept volume decomposition based hexahedral mesh generation,aims to support the automatic generation of high-quality hexahedral meshes for complex solid models.The main contents of this dissertation are presented follows:A swept volume decomposition approach based on sweep direction extraction is proposed.Firstly,the potential swept volumes of the model are identified based on the relationship between the sweep direction and the surface of the swept volume,and then the optimized cutting face sets are constructed by determining the normal and position of the cutting surfaces to recursively divide the intersecting potential swept volumes.Finally,the model is decomposed into a set of sub-volumes that include all swept volumes of the model.This method can effectively identify all swept volumes of the model including severely intersecting ones.A pseudo-swept volume decomposition approach based on fuzzy clustering is proposed.Firstly,all potential pseudo-swept volumes of the model are identified based on fuzzy clustering,and then the intersecting potential pseudo-swept volumes are separated by a greedy strategy-based optimized cutting face set construction algorithm.Finally,the model is decomposed into a set of sub-volumes that include all pseudo-swept volumes of the model.The method can effectively identify and decompose the pseudo-swept volumes in the model,thus enabling the automatic decomposition of more complex CAD models.A global approach to multi-axis swept mesh generation is proposed.Firstly,the surface meshes satisfying certain constraints are generated globally for all the swept volumes,then the swept mesh is generated for each swept volume.Finally,a set of topological modification operations are performed to improve the topological quality of the generated mesh.This method can generate high-quality hexahedral meshes based on the swept volume decomposition results.In addition,the method can support the processing of the swept volume decomposition results with complex grafting relationships,to meet the requirements of high-quality hexahedral mesh generation for complex models.A prototype system called HexGen is developed.Meanwhile,some experiments are conducted to validate the main ideas of the proposed approaches.