【作者】 刘远祥；

【导师】 李小宁；

【作者基本信息】 南京理工大学 ， 机械制造及自动化， 2006， 博士

【摘要】 虚拟加工过程(VMP——Virtual Machining Process)是在对产品几何参数、材料物理性能、切削参数及加工的物理过程进行全面建模的基础上，利用数值仿真技术，在计算机内对加工过程的虚拟实现，主要用于分析真实加工环境中各因素对加工过程的影响，预测加工结果，评估零件的可加工性，优选加工方案，优化工艺参数，是一种直观、经济、高效的技术途径。 论文以易变形薄壁零件的数控立铣加工过程作为主要对象，系统地分析了虚拟加工中涉及的技术方法，针对目前数控仿真研究中普遍采用的几何模型不适用于虚拟加工过程、还没有适用于易变形工件切削过程的力学模型、工件受力变形分析所采用的有限元方法效率太低等主要问题，进行了深入研究。 首先，从虚拟加工过程的技术需求分析出发，论文提出了一个虚拟加工平台的体系结构；围绕实现工件受力变形快速模拟和分析这一目标，分析了系统各组件间的相互关系，以及实现这些组件所需的技术，为关键技术研究工作和软件开发提供总体框架。这些关键技术可以归类为虚拟加工过程建模技术和工件变形的快速分析技术。 虚拟加工过程建模技术是分析切削过程中工件的受力变形的基础。论文研究的建模技术主要包括：能够满足虚拟加工过程需求的工件模型：用于确定工件变形边界条件的装夹模型和用于描述易变形工件在加工过程中刀具运动、实际切削量、切削力分布以及工件变形量等之间相互关系的挠性工件切削过程力学模型。 此外，论文研究了立铣加工中常见的薄壁类型和相应的受力变形解析(或解析与数值相结合)算法，在此基础上构建了基本薄壁元素及其变形算法库，可以为基本薄壁元素变形快速估算提供算法支持；为减小局部快速分析可能带来的误差，提出了对关键点变形量进行有限元和实验校核以获得可靠的校正系数的方法。 论文中提出的最小壁厚法、关键点法和预置区域法等技术手段，可用于在虚拟加工过程中识别工件变形的敏感区域；并结合构建的基本薄壁元素与变形算法库，将变形量快速估算与重点位置的少量有限元精确分析相结合，构成虚拟加工过程高效分析流程，在保证精度的基础上显著提高分析效率。 论文最后利用研究成果开发了原型系统BaseVMP，并通过一个典型薄壁零件加工过程进行了实验验证，结果显示可以利用虚拟加工技术优化切削参数，缩短加工工时。更多还原

【Abstract】 VMP (Virtual Machining Process) is a kind of virtual realization of machining process in computer based on a comprehensive model, which takes account of geometric parameter of part, material property, cutting condition and physical process of cutting. It is expected to analyze the effect of geometric and physical aspects on cutting process, so as to predict the machined result, evaluate machinability of part and optimize machining parameter. It is an intuitional, efficient and economic approach.In this dissertation, which concentrates on the virtual machining process of the NC end milling of thin-walled workpiece, the relative techniques of virtual machining are reviewed. Then three themes are induced, which constitute the main research contents of this dissertation. They are as following: geometric models in NC simulation are not suitable for virtual machining process, there isn’t suitable mechanics model to the machining process of flexible workpiece, and it is impractical to analyze deformation using FEA (Finite Element Analysis) totally in the whole virtual machining process for its low efficiency.According to the requirement analysis of virtual machining technology, a new architecture is proposed to provide a framework for the development of software and the research of key techniques. These key techniques can be classified to modeling technique and analysis accelerating technique.Modeling is the foundation of deformation analysis. In this dissertation, three models are studied. They are workpiece model which meet the requirement of virtual machining process, fixture model which is used to prescribe the boundary conditions for deformation analysis, and mechanics model of cutting process of flexible workpiece which is apply to describe the relationship of cutter movement, actual cutting quantity, cutting force distributing and workpiece deflection.Furthermore, the analytical (semi-analytical) algorithms are studied to calculate deformation rapidly for the thin-walled structures, which frequently appeared in end milling. Then a library of typical thin-walled components with their deformation algorithms is established to support the analysis accelerating technique. The deformation at key position is calibrated to compensate the inaccuracy of the rapid analytical algorithms in the library.更多还原