Multi-scale modeling of the thermal workpiece load in the turning process considering the cutting fluid

切削液的使用在机械加工技术中是有益的，以便传输从工具-工件界面产生的工艺热，并由于其润滑作用而减少摩擦热。在这种情况下引起的热机械载荷对部件的表面完整性和相关功能性具有相当大的影响。然而，在以前的工作中，工件的热负荷和机械负荷已被单独建模。为了全面理解这一过程，有必要研究机械和热现象之间的相互作用。因此，提出的研究项目的主要目标是在车削过程中的热工件载荷的多尺度建模，考虑到切削液的供应和刀具磨损条件。在第一个资助期，开发了计算流体动力学（CFD）和有限元法（FEM）之间的耦合方法。耦合方法是基于有限元和计算流体力学之间的机械和热参数的迭代交换。基于有限元模拟和实验，切屑的几何形状进行计算，并作为输入的CFD网格生成。在计算流体力学模拟中，传热系数然后被量化并转移到有限元模拟中，然后有限元模拟计算修改的芯片几何形状。此外，进一步的子模型的开发和验证的摩擦行为的描述，以及在考虑切削液的接触传热。总的来说，这种迭代耦合方法可用于确定加工过程中复杂部件边界层中的温度分布和梯度。通过将有限元切屑形成模拟增强到考虑摩擦和热传递模型的实际摩擦学条件，填补了建模方法中的一个主要科学空白，从而可以实现真实的条件下的加工过程的全面虚拟图像。

The use of cutting fluid is beneficial in the machining technology in order to transport the process heat generated from the tool-workpiece interface and to reduce the frictional heat due to its lubricating effect. The thermo-mechanical load induced in this context has a considerable influence on the surface integrity and the associated functionality of the component. However, the thermal and mechanical load of the workpiece has been modeled separately in previous work. For a comprehensive understanding of the process, the investigation of the interaction between mechanical and thermal phenomena is necessary. Therefore, the main objective of the proposed research project is the multi-scale modeling of the thermal workpiece load in the turning process, considering the supply of cutting fluid and the tool wear condition. In the first funding period, a coupling approach between Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) is developed. The coupling approach is based on the iterative exchange of mechanical and thermal parameters between FEM and CFD. Based on FEM simulations and experiments, the chip geometry is calculated and used as the input for CFD mesh generation. In the CFD simulation, the heat transfer coefficients are then quantified and transferred to the FEM simulation, which then calculates the modified chip geometry. In addition, further sub-models are developed and validated for the description of the friction behavior as well as the contact heat transfer under consideration of cutting fluid. Overall, this iterative coupling approach can be used to determine the temperature distribution and gradients in the boundary layer of complex components during machining. By enhancing the FEM chip formation simulation to the actual tribological conditions considering friction and heat transfer models, a major scientific gap in modeling approaches is closed, and thus a comprehensive virtual image of the machining process under real conditions can be achieved.