Research And Practice On Reconstruction And Process Analysis For Automobile Panels

With the development of the integrative world and increasingly competitive market after entering WTO, it looks specially important and urgent how to use the advanced theory, methods and digital information technology to establish the core technology and development platform with independent knowledge property right and market competitive power by introducing into, assimilating and accumulating the foreign technology, so as to realize independent innovation and development, gradually walk out of the plight of being restricted by the foreign companies in technology and the lower innovative ability, and shorten the gap of auto industry between the developed countries and China as quickly as possible. Therefore, as the key part of auto-body, the panels are researched about the related theory and methods of reconstruction and processes analysis, which is nuclear in this thesis. Firstly, on the basis of analyzing research status and shortage about 3D reconstruction and process analysis of automobile panels, the main research contents of this thesis are proposed. And the definitions and traits of automobile panels and 3D reconstruction, research reasons of 3D reconstruction and the purpose and learned significance of this thesis are set forth.Secondly, based on the theories of computer graphics and computer aided geometric design, and according to the traits of automobile panels, the related theory and experience about 3D geometric expressing of automobile panels are described. It is studied to the constitution methods of typical surfaces forming the surfaces of automobile panel, fairing quality and error analysis and optimization of reconstruction surfaces, and the storage structure of 'half' edge for 3D model, data changes in different stamping steps and data exchange among the different software. The constitution methods of converged surface based on the shape of around surfaces are proposed. Meanwhile, the key technologies of 3D reconstruction for automobile panels are especially researched, which includes: after analyzing four data sources, which are engineering drawings, product, electric information and design thought, of reconstruction and their characteristics, the methods and flows of 3D reconstruction based on the different data sources are proposed; studied the technology of surface segmentation and splicing and blending of complicate surfaces and the difficult cases; the design criteria and specifications of 3D model and the basic framework of designingbased on the forward and 3D reconstruction design idea for automobile panels are also established and studied; and the flow of surface reconstruction and the methods of data process based on engineering drawings and point cloud of die surface is put forward and researched.Thirdly, after analyzing the characteristics of basic stamping steps, formability and the reasons and precautionary measures of stamping defects about automobile panels, such as wrinkle, crack, spring back and so on, and by discussing the establishing process and quality evaluation of process models and the typical methods of process analysis of automobile panels, the influence of process analysis on automobile panels design is studied, which combines the factors of automobile panels design. The quality of 3D reconstruction design is also partly validated. And design method integrated FEM simulation for the panels is summarized and proposed.Lastly, the above systematic theory and methods are successfully applied for the virtual prototype technology for a car in a joint-stock motor company, and many good remarks are got...