【作者】 李涛；

【导师】 鲁世红；

【作者基本信息】 南京航空航天大学 ， 材料加工工程， 2007， 硕士

【摘要】 切削加工是一个高度非线性、热-力耦合的过程,难加工材料的切削加工已经成为当前制造业发展的重要方向,也是国内外学者争相研究的热门领域之一。鉴于切削过程的复杂性,不能单靠原始的办法研究难加工材料的切削技术。随着计算机性能的不断提高,使得运用计算机仿真技术模拟切削过程成为了可能。本文以H13淬硬钢为研究对象,主要研究工作及创新点包括:应用金属切削、剪切滑移理论和温度场理论,建立了H13钢材料的正交切削模型,描述了切削过程中的力学行为,并运用试验数据进行了验证;根据二维应力波理论在Hopkinson压杆上进行了高应变速率下的压缩试验;获得了H13钢在高应变速率条件下的流变应力数据,拟合了Johnson-Cook本构模型中各参数;在C630车床上进行了H13钢在不同切削速度和切削厚度条件下的正交切削试验,获得了各种切削参数下的动态切削力变化特征,分析了各种切削参数对切削力的影响情况,并对切屑形态进行了微观分析;基于热-弹塑性有限元方程并在一定假设的条件下,建立了金属正交切削加工的热力耦合有限元模型,分析、研究了切屑分离标准、刀屑界面的摩擦模型以及热控制方程等切削加工模拟所涉及的关键技术进行了深入研究,通过改变切削参数,实现了不同条件下切削过程的系列模拟,研究并分析了正交切削条件下各参数的变化情况,并与试验值进行了对比验证。本文将高应变速率下的本构关系运用到淬硬钢的切削当中,为难加工材料的切削加工和计算机仿真研究提供了源头数据,为淬硬钢的切削加工提供了理论指导。更多还原

【Abstract】 Metal cutting is a process with exceeding non-linear and heat-stress coupled. Hard cutting has become the main developing direction in manufacture industry, and also is one of the domains being studied by many scholars both in home and abroad. Due to the complexity of the cutting process, using only one method to analyze the whole process is not enough. With the fast development of the computer technology, applying the computer simulation technology to simulate the metal cutting process has become possible. This paper studies H13 hardened steel, the main research work and the improvement include:Firstly, according to the theory of metal cutting, shear and glide and temperature field, an orthogonal cutting model was set to describe the metal cutting behaviors of H13 steel, and the model was verified by experimental data. . Secondly, high strain rate compression experiments were performed on the Hopkinson bar according to the two-dimensional stress wave theory to obtain the stress-strain data and the parameters in the Johnson-Cook constitutive model were fitted. Thirdly, a serious of orthogonal cutting experiments were carried out on the C630 lathe under different cutting parameters. The dynamic cutting force was investigated and the chip microscopic analysis was taken. Lastly, based on thermo-elastic-plastic finite element equation, an orthogonal cutting model was established under some assumptions. By MSC.Marc software the critical techniques including grid division, chip formation as well as separation criterion were investigated thoroughly. By changing parameters, a series of simulation at different cutting conditions were come to true, the parameters in the orthogonal metal cutting course were analyzed, and the findings were validated with the former experimental results.The construction data in high strain rate is used in hard cutting, which has provided the source data results for the hard cutting and computer simulation.更多还原