In situ strain measurement in metal cutting with geometrically defined cutting edge

具有几何定义的刀具刃口的加工过程具有高度复杂的切屑形成过程。已经开发了许多模型来描述切屑形成过程中的物质流动。这些模型可用于计算切屑形成区的力学和热状态变量，如应变、应力和温度。然而，由于切割过程难以监控的情况，切屑形成模型依赖于几个简化的假设。第一个项目期的主题是利用高能同步辐射X射线原位测量切屑形成区内的应力状态。确定了不同的切削参数对应力状态的影响。这些发现有助于验证和推广现有的切屑形成模型。应在第二个项目期考虑进一步影响应力状态的变量。这些变量是组合边缘的形成、多相材料以及材料中微观结构的变化。微观组织变化的材料参数应通过ECAP实验(等通道转角挤压)确定，并应在切割模拟模型中实施。随后，材料的微观结构属性将在切割模拟中发生变化。因此，可以研究它们对应力状态的影响。

The machining process with geometrically defined cutting edge is characterized by a highly complex chip formation process. A number of models have been developed which describe the material flow during chip formation. These models can be used for the calculation of mechanical and thermal state variables in the chip formation zone, such as strain, stress and temperature. However, the chip formation models rely on several simplifying assumptions due to the circumstance that the cutting process is difficult to monitor. The subject of the first project period was the in situ measurement of the state of stress within the chip formation zone during the cutting process by means of high-energy synchrotron X-radiation. The influence of different cutting parameters on the stress state was to be determined. The findings contribute to the verification and extension of existing chip formation models. Further influencing variables on the stress state shall be considered in the second project period. These variables are the formation of built up edge, a multiphase material as well as microstructural changes in the material. Material parameters for the microstructural changes shall be determined by means of ECAP experiments (Equal Channel Angular Pressing) and shall be implemented in a cutting simulation model. The microstructural material properties will subsequently be varied in the cutting simulations. Their influence on the stress state can thereby be investigated.