【作者】 姜杉；

【导师】 王玉新；

【作者基本信息】 天津大学 ， 机械设计及理论， 2004， 博士

【摘要】 本文密切结合现代零件设计和制造过程中所关心的瓶颈问题,在教育部985基金项目“三维虚拟机械产品开发自动化平台构建理论研究”资助下,以典型零件为例,建立了基于特征零件结构并行设计系统,提出了运用特征技术进行零件结构并行设计的新方法。主要研究内容如下: 从并行工程的理论出发,构建了基于特征的零件结构并行设计环境,分析并指出了其关键技术,建立了整个零件结构设计系统的总体框架和设计流程,阐述了该系统在三维机械虚拟创新设计中的重要地位和作用。重新赋予设计特征、制造特征、工艺特征和评价特征新的含义,并首次提出了中性特征的概念。通过功能需求与应用特征间的分层映射关系将概念化的需求特征转化为具体的结构形状和约束,进而利用广义布尔运算将映射后的特征根据约束关系进行具体零件结构建模。在设计特征和制造特征之间首次提出一种混合特征映射机制。即对于设计域中的形状特征与制造域中的加工形状特征,采用直接映射机制。而对于制造过程中所需使用的非几何信息则采用以中性特征为桥梁的间接映射机制。从而为CAD/CAPP/CAM 集成提供完整的设计信息。首次将一种非线性的工艺规划方法—AOS树理论应用于箱体类零件,用AOS树的结构形式完整表达工艺规划所需的工艺特征信息集,通过对AOS 树进行整合和遍历,获取待加工零件的工序、工步以及加工过程中所需要的制造资源。为后续零件的可制造性评价奠定了坚实的基础。首次将层次分析法(AHP)用于机械零件的多目标优化过程中。针对可制造性评价函数所涉及的多因素和量纲不统一问题,分别建立各评价因素的线性归一化的目标函数,运用AHP 方法确定各评价因素的权重因子。据此,将权重因子和各分目标函数带入统一的评价函数,得出最优目标值,并以此确定出最优设计方案。自主开发了一套适用于箱体类和轴类零件设计的软件系统。该系统以Windows2000 操作系统为依托,运用VC++6.0 编程工具实现了基于特征的零件并行设计,并对SolidWorks2000 参数化造型平台进行二次开发实现了系统的实体造型功能。更多还原

【Abstract】 According to the requirements of advanced part design and manufacturing process, and some representative parts as examples, a feature-based concurrent design methodology is put forward and a system for part structure is built up. All these works are supported by “985”project fund of ministry of education, Research on the exploitation of automatic system for 3D virtual mechanism. The main outcomes in this paper are stated as follows: A feature-based concurrent design condition for part structure is given on the basis of the concurrent engineering theory. Moreover, some key technologies are also analyzed systematically at the same time. Then, the framework and procedure of the whole system are built up respectively. At last, the status and functions of above system on the 3D virtual mechanism creative design are discussed extensively. The features of design, manufacturing, technique and evaluation are reinterpreted and a new kind of feature, that is neutral feature, is defined for the first time. Through the delamination mapping among these features, the nonfigurative requirement can be transformed into 3D structure shapes and constraints. After that, generalized Boolean operation is used to build the detail part model with the constraints. A mixed mapping methodology is put forward between the design feature and manufacturing feature: the direct mapping is used for the transformation between the shape feature of design field and manufacturing field; the indirect mapping between the design region and manufacturing region that is bridged by the neutral feature is used for the nongeometry information mapping. So the whole design information can be provided for the CAD/CAPP/CAM. AOS tree, a nonlinear methodology for process planning, is used in the box part design for the first time. It can depict the data of process planning perfectly. After searching the detail AOS tree, the working step, procedure and manufacturing resource can be calculated at the same time. Thus the solid foundation for the manufacturing evaluation of part is laid. Analytic Hierarchy Process (AHP) method is used in the multi-objective optimization for part structure for the first time. First, because all the factors will affect the evaluation result simultaneously, different sub-objective functions are built up for different measure factors. Then, AHP method is used to confirm weighting coefficients of the evaluation factors. Furthermore, weighting factors and sub-objective functions that are normalized linearly are taken into evaluation function. According to above function, the evaluation result can be received, and the optimized scheme of part structure can also be gained. A feature-based concurrent design software is developed for axial and box parts. This software is relied on the Windows 2000 and VC++6.0, and the 3D modeling function of the software is build on redeveloping of the SolidWorks-2000.更多还原