【作者】 王素玉；

【导师】 艾兴；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2006， 博士

【摘要】 高速切削加工是近20年来迅速发展起来的先进制造技术，以高切削速度、高进给速度和高加工精度为主要特征，具有综合效益高、对市场响应速度快的能力。对于这一崭新技术，在实际生产中，尚有许多新的问题有待于解决，不仅牵涉到技术研究层面上的问题，更主要的是理论研究层面上的问题，迫切需要建立与高速切削系统相匹配的理论体系和研究方法。尤其是在不均匀热-力耦合强应力场作用下，已加工表面的形成过程及对表面质量所进行的系统、全面研究很少，使得有效控制高速切削加工表面质量的理论基础尤显不足。论文基于高速切削理论、热-弹塑性变形理论和有限元理论对高速切削机理及表面加工质量进行了研究，从理论上创造性的提出了高速切削变形区不均匀强应力场的热-力耦合理论，并应用到已加工表面粗糙度、表面硬化程度和残余应力性质机理的研究中，对深入探讨切削参数、工件材料等对与加工表面质量的影响规律具有重要的理论指导意义，为高速切削技术的推广和应用提供可靠的、科学的依据和技术支撑。 探讨了适合高速切削变形的不均匀热-力耦合强应力场的建模及有限元模拟方法。根据热-弹塑性变形理论、有限元方法，建立了受应变、应变速率和切削温度影响的材料应力-应变关系本构方程，材料为均质、等向强化的塑性材料，符合Prandtl-Reuss应力增量理论及Von Mises屈服准则：基于Oxley切削理论，构建了适于高速切削的扩展的Oxley切削模型，设定了相应的有限元模型边界条件，利用大型有限元分析软件DEFORM-2D、DEFORM-3D对高速切削过程进行了二维和三维动态切削过程模拟，模拟结果表明，高速切削变形区为一个不均匀、高梯度、非线性的热-力耦合强应力场。通过系统、深入地分析高速切削变形区刀-屑、刀-工接触面及剪切区应力场和温度场的分布规律，为课题的后续试验分析和研究工作提供了可量化和可供参考的数据。 建立了已加工表面分析模型，分析了已加工表面的形成过程，研究了高速切削变形区的剪切区、刃口区、后刀面摩擦磨损区对工件已加工表面的应力场、温度场的影响；用一定刃口钝圆、后刀面磨损带的刀具进行了高速切削模拟，反映了刀具-工件接触区的应力场及温度场分布的变化规律。更多还原

【Abstract】 High-speed machining (HSM) is one of the advanced manufacturing technologies in the last two decades, which is characterized by high speed, high feed rate and high precision. It is a cost-effective manufacturing process to produce parts with higher surface quality and can adapt to the keen competition and rapid change of the market. HSM technology has already been applied in many manufacturing industries. In practical operations, there are numerous new problems arising for both technical and theoretical aspects which need to be urgently solved. Surface quality is one of the most important factors in evaluating machining productivity and cutting performance, which is a significant design specification known to have considerable influence on parts properties such as wear resistance, ductility, tensile, and fatigue strength. However, the shortages of researches on surface quality predication and controlling techniques limit the development and reasonable application of the HSM technology, especially in studying the formation mechanisms of the machined layer affected by the non-uniform thermo-mechanical coupling intense stress fields in high speed cutting zones. Consequently, the surface integrity of the machined layer for high-speed milling is investigated based on the high-speed machining theory, thermo-elastic-plastic deformation theory and Finite Element Method (FEM) in the paper. The theory for the non-uniform thermo-mechanical coupling intense stress fields in high speed cutting zones is presented and applied to the analysis of the formation mechanisms of surface roughness, residual stresses and surface hardening. It is an important fundamental subject to promoting HSM technology development and application, which has a very important theoretical and practical significance to exploit HSM potential energy further. The modeling and analysis for the non-uniform thermo-mechanical coupling intense stress fields in high speed cutting zones are conducted on the basis of the thermo-elastic-plastic deformation theory and FEM techniques. The stress-strain constitutive equation of plastic materials in large plastic deformations is presented to follow the Prandtl-Reuss flow rule and the Von Mises yield criterion, possessing isotropically strain hardening characteristics. Meanwhile the flow stress is taken as a function of strain, strain rate and temperature. A new orthogonal cutting model for HSM is constructed according to Oxley’s machining theory. The applicability of Oxley’s machining theory is extended to the HSM. FE simulations are performed by using更多还原