Characterization and simulation of the fracture behavior of CBN grain types as a function of crystal structure, grain orientation and dressing parameters

CBN 晶粒类型断裂行为随晶体结构、晶粒取向和修整参数变化的表征和模拟

• 批准号: 391202973
• 负责人: Professor Dr.-Ing. Thomas Bergs, since 7/2019
• 金额: --
• 依托单位: Werkzeugmaschinenlabor - WZL
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/391202973?language=en
• 关键词: Characterization; simulation; fracture; behavior; CBN

The grinding process is at the end of a multitude of value-added chains and contributes decisively to the application behavior of components. During the grinding process, the edge zone of these components is influenced by a thermo-mechanical and material-metallurgical stress collective. This determines the components edge zone properties. These properties depend on the contact conditions between the grinding wheel and the workpiece acting in the grinding process. A change in the grinding tools topography therefore has a significant influence on the load collective and thus on the grinding process result. In order to predict topographies, recently developed mathematical-generic grinding tool models exist that depict the spatial arrangement of the components grains, binding and pores in a realistic manner as a function of the volumetric composition of a grinding tool. With the aid of this software-based model, grinding wheel topography will be predicted in the future without having to measure the grinding wheel topographies. Out of this, software-based models allow a prediction of the kinematic contact conditions between the grinding wheel and the workpiece, which determine the application behavior as well as the process result. The kinematic contact ratios depend to a large extent on the used breaking behavior of the grain material. However, the fracture behavior of commercially highly relevant grain materials, such as the cubic boron nitride (CBN), is investigated insufficiently.Therefore, the aim of the present research project is an explanation model for the characterization of the fracture behavior of CBN grain materials taking into account the crystal shape of the grain type, the crystal orientation and the dressing parameters.To this end, a method for the quantitative analysis and description of the fracture behavior of CBN grain materials is developed first. Furthermore, the fracture mechanisms of CBN grain materials are investigated in a single-grain dressing process as a function of the crystal shape and the dressing parameters. Based on the findings of the empirical investigations, a numerical modeling of the stresses during the dressing process in CBN grains is carried out and a transfer of the findings to the existing software-based models for the simulation of the grinding tool topography is done. In the future the empirical findings and simulation results are used to simulate grinding processes depending on the specification of the used grinding tool. This offers the potential to substitute cost-intensive empirical series of experiments by simulations, and thus to determine the effects of the resulting grain-breakage-dependent grinding wheel topography on the process behavior as a function of the volumetric composition of the grinding wheel and the dressing process.

研磨过程处于众多增值链的末端，对部件的应用行为起着决定性的作用。在磨削过程中，这些零件的边缘区域受到热机械应力和材料冶金应力的影响。这将确定组件的边缘分区特性。这些特性取决于磨削过程中砂轮和作用于工件之间的接触条件。因此，磨具表面形状的变化对载荷的集中，从而对磨削过程的结果有很大的影响。为了预测形貌，最近开发的数学-通用研磨工具模型以现实的方式描述了作为研磨工具的体积组成的函数的成分颗粒、结合和气孔的空间排列。借助这个基于软件的模型，可以在不测量砂轮形貌的情况下预测未来的砂轮形貌。此外，基于软件的模型可以预测砂轮和工件之间的运动接触条件，这些条件决定了应用行为和加工结果。运动接触比在很大程度上取决于颗粒材料的破碎行为。然而，目前对立方氮化硼(CBN)等商业相关性较高的颗粒材料断裂行为的研究还不够深入，因此，本研究的目的是建立一种能够描述立方氮化硼(CBN)颗粒材料断裂行为的解释模型，该模型综合考虑了立方氮化硼(CBN)颗粒材料的晶型、取向和修整参数。此外，还研究了CBN颗粒材料在单晶修整过程中的断裂机制与晶体形状和修整参数的关系。在实验研究结果的基础上，对CBN磨粒修整过程中的应力进行了数值模拟，并将结果传输到现有的基于软件的磨具形貌模拟模型中。在未来，根据所用磨具的规格，使用经验结果和模拟结果来模拟磨削过程。这提供了通过模拟取代成本密集型经验系列实验的可能性，从而确定所产生的依赖于磨粒破碎的砂轮地形对过程行为的影响，作为砂轮的体积成分和修整过程的函数。