Research On CAx Integrated Shape Modeling Method For Automobile Styling

With the growth of diversified demand and the intensification of market competition,how to increase the R&D efficiency of automobile modeling has become a problem faced by many car companies.Computer-aided modeling software based on human-computer interaction has become more and more widely used in the conceptual design phase of automobiles,becoming one of the indispensable tools in the conceptual design phase of the vehicle body.However,the shape modeling based on human-computer interaction is very demanding and expensive for engineers,and the digital design and manufacturing process models are highly heterogeneous.Therefore,the conversion of the design intent of the automobile stylist to the digital model is needed,and the integrated modeling of the vehicle body conceptual model with high efficiency and high quality needs to be solved.In order to achieve high-speed modeling of high-quality vehicle body model,this paper begins with the vehicle body characteristic line network oriented to the deformation model,conducts in-depth research on the description methods and quality assessment of the characteristic curve and surface,and proposes to recode the car body curve network.Smooth solution,so as to achieve a high-quality body curve network can be processed for different body curves.After analyzing the structure of the car body and the type of the surface,four kinds of car body surface segmentation strategies are adopted for different types of car bodies,thereby realizing automatic generation of a high-quality car body surface model.In order to meet the needs of rapid prototyping and simulation,through the sampling of existing vehicle models,more than a hundred models of grid deformation templates were constructed,and grid-driven deformation technology was used to achieve high-quality grid model-oriented simulation and manufacturing.The work of this article mainly starts from the following aspects:(1)High-quality car body surface model: research on the existing mainstream A-level surface modeling tools,summarizing the method of constructing A-class surface,and presenting the concept of “quasi-A-level” surface,combining the methods of mainstream modeling tools The body curve network proposes a corresponding body curve network optimization method,so as to realize the smoothness of the body curve network,and lays a foundation for generating high-quality body curves.Through the classification of vehicle models and the analysis of modeling surfaces,four different strategies for car body surface creation are proposed,so that the quality of car body surfaces is conducive to the subsequent deformation of car body grids.(2)High-quality body mesh model: The selection principle of the prototype vehicle during the body mesh deformation process was studied,and 99 body mesh deformation templates were proposed for most current models.The quality of the grid deformation of the vehicle in the current shape space is guaranteed.In the end,the optimization method of the vehicle body characteristic line in this paper is implemented by using MATLAB,the surface smoothing of the car body is completed,and the example verification of different hand-drawn sketch input is performed.A large number of numerical calculation results prove the high-quality body concept based on the car body feature line network proposed in this paper.Feasibility and Reliability of Model Selection Method and Grid Deformation Template Selection Principles.Based on the method proposed in this paper,the body curve network database was updated,and a large number of body mesh models were generated to facilitate the use of follow-up work.