【作者】 杜亭；

【导师】 李志刚； 柳玉起；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2008， 博士

【摘要】 计算机辅助工程(CAE)技术是现代先进制造技术的重要组成部分,也是企业提升产品、工艺、模具设计水平,摆脱传统经验型设计的关键。随着有限元数值方法、冲压成形理论研究的不断深入以及计算机技术的迅速发展,板料成形模拟技术逐渐成熟并摆脱了早期只能应用于单工序拉延模拟的局面,可以完成从重力效应到回弹在内的全工序虚拟试模,以适应不断发展的制造工业的需要。与此同时,由于具备了传统CAE系统不具备的无缝集成与数据无损的优势,CAD/CAE一体化集成系统不断完善,实现“CAE驱动设计”已成为近年来CAD/CAE系统发展的重要方向。论文结合国家自然科学基金资助项目(No.50575080)、国家科技支撑计划资助项目(No. 2006BAF01A43)和国家863计划基金(No. 2006AA04Z140),对板料成形模拟的核心求解器、前后处理关键技术、CAD/CAE集成技术等进行了深入研究,并在此基础上开发了国内首个板料成形全工序模拟系统FASTAMP/Multi-process和国际首个面向设计全流程的CAD/CAE集成系统FASTAMP-NX。针对传统动力显式算法中拉深筋阻力、摩擦力等工艺参数数值模型无法反映约束阻力真实作用效果的问题,提出了基于真实工艺参数的动力显式算法,可以更加精确地反映实际成形过程中工艺参数所引起的约束阻力的作用效果。首次将网格自适应加减密技术引入到动力显式算法,开发了达到工业实用化水平的动力显式算法核心求解器。对板料成形模拟系统的一些关键技术,如数据文件接口、曲面描述、网格剖分算法等,进行了深入研究。加强了FASTAMP系统数据文件接口的兼容性和稳定性;提出了新的独立裁剪曲面工具网格剖分和修复算法,开发了相应的工具网格剖分器,避免了网格质量问题所引起的网格修复工作,大大减少了有限元分析模型准备的工作量;提出并实现了新的裁剪坯料网格生成算法,与传统的有限元网格剖分算法相比,网格质量生成质量有了很大的提高,有助于改进求解器的计算精度。在对板料成形模拟关键技术研究的基础上,研究开发了国内首个面向汽车覆盖件和级进模的板料成形全工序模拟系统FASTAMP/Multi-process,实现了包括重力效应、压边过程、拉深(拉延)、弯曲、成形、工艺切口、冲裁、修边、翻边、折边、回弹在内的全工序模拟功能。基于UGS NX平台开发了国际首个面向设计全流程的全参数化CAD/CAE集成系统FASTAMP-NX。系统包含了面向设计的IAW(Inverse Approach Wizard)和面向虚拟试模的FAW(Forming Analysis Wizard)子系统,实现了全参数化的―建模-分析-制造‖流程,克服了传统CAE软件无法实现实时―设计-修改-再分析‖的局限,可以应用于产品设计、工艺设计、模具设计、虚拟试模的全流程。更多还原

【Abstract】 Computer Aided Engineering is an important part of advanced manufacture technology, and is the key to improving the ability of product design, process planning, and die design and for enterprises changing the traditional design style depending on experience for enterprise. With the development of computer technology, in-depth study of finite element numerical method and stamping deformation theory, the technology of sheet forming analysis has been gradually matured and could be applied in the complete stamping process from gravity effect to springback evaluation to meet the requirements of manufacturing industry. At the same time, CAD/CAE integrated systems have been developed, which have the advantages of seamless integration and no data loss over the traditional CAE systems. The development of CAD/CAE integration technique greatly expands the application scope of CAE technology, and gradually approaches the aim of CAE-driven design process.The work of this paper was supported by a grant from National Natural Science Foundation of China (No.50575080), National Key Technology R&D Plan (No. 2006BAF01A43) and National High-Tech Plan Project (No. 2006AA04Z140). On the basis of the in-depth study on the key technologies such as solver, pre-processing, post-processing and CAD/CAE integration, the first domestic sheet forming analysis system for the complete stamping process planning named FASTAMP/Multi-process and CAD/CAE integrated system named FASTAMP-NX have been developed.A new technique of constraint resistance treatment by the means of linear elastic spring element model in sheet metal forming process is proposed based on the dynamic explicit incremental method, which can be applied to build the more accurate model of process parameters such as blank holding force, drawbead and friction, to reflect the effect of the process parameters. An adaptive mesh refining and coarsening has been developed, and applied to the solver of the developed improved dynamic explicit incremental approach. As a result, the simulation time consumed is greatly reduced, and an ideal balance between time consumed and calculation precision is achieved.The key techniques for sheet forming analysis system, such as CAD data transfer interface, curve and surface description and mesh generation, have been studied in-depth. The compatibility and stability of intermediate data transfer interface for FASTAMP is greatly enhanced .Based on independent surface trimming, a new meshing algorithm is developed for tool mesh generation and auto-repairing so that the mesh quality is obviously improved, and the time consumed for FEA model building and mesh repairing are greatly reduced. The new initial blank mesh generating algorithm based on outline trimming is also proposed, which can be applied to get better mesh quality than traditional part mesh generating algorithm.Based on the research of the key technologies, a sheet forming analysis system named FASTAMP/Multi-process for the complete stamping process planning for the automobile panels and progressive tooling has been developed. It enables analyzing the entire sheet forming process– from blank feeding into the press, to binder wrap, drawing, trimming, restriking, flanging, bending and springback so that the number of die tryouts is reduced, , and the lead-time for tooling development is reduced.A parametric CAD/CAE seamlessly integrated system named FASTAMP-NX has been developed based on UGS NX platform, which includes two subsystems, IAW for design of sheet metal parts and stamping dies and FAW for virtual tryout. With the unique parametric feature model and associated design technology, the integrated system can be applied to the whole process of the product and die development, including conceptual design, detail design, process planning and virtual die tryout to realize the real CAE-driven design process, the final goal of CAE.更多还原