Development of prediction models for deviating, thermo-elastohydrodynamically lubricated contacts (DeviaTEHD)

降低机械零件润滑接触的摩擦损失是开发节能耐磨技术产品的重要策略。除了润滑条件、运动类型或几何形状外，摩擦损失的一个原因是部件在制造过程中发生的表面形貌偏差。由于表面的波纹度和结构，表面的偏差可能会在不同程度上导致摩擦损失。为了开发具有润滑接触的高能效机械元件，在设计时需要对现有的热弹流体动力(TEHD)接触进行精确计算，并考虑与生产的偏差。无限长线和三维点接触的润滑膜和压力参数的计算已经有了广泛的、解析可解的近似计算方法。然而，这些没有充分考虑到每个部件中发生的制造偏差。同时，有可靠但耗时的模拟工具用于TEHD接触计算。然而，在产品开发过程的背景下，当用于多体或系统模拟时，简单且省时的应用是对所使用的计算模型的基本要求。由于缺少对偏差接触的准确计算的近似，计划中的研究项目的目标是开发预测模型，以确定在考虑表面偏差的情况下，集中接触中的中心和最小润滑膜厚度以及最大压力和温度。为此，将表面的波形偏差参数集成到无限长二维线接触和三维点接触的TEHD仿真模型中。使用座椅自身的TEHD模拟工具Tribofem，对这两个模型进行分析，以确定对润滑膜形成和接触中压力分布的影响，并生成数据库。在这个数据库的基础上，通过在Dowson/Higginson或Blok/Moes的近似公式中引入一个额外的修正因子，利用数学回归和现代机器学习方法等更复杂的方法，建立了无限长线和三维点接触的预测模型。通过对预测模型的准确性、可用性和时效性等指标的评价，选择了一种适用于线接触和点接触的预测模型。在本研究项目的最后，将通过一个应用实例来说明其在产品开发中的适用性。

The reduction of friction losses in lubricated contacts of machine elements is an important strategy for the development of energy-efficient and wear-resistant technical products. In addition to the lubrication condition, the type of motion or the geometry, one cause of friction losses is deviations of the surface topography of the components, which occur during manufacturing. The deviations of the surface can contribute to friction losses due to the waviness and structure of the surface to varying degrees. In order to enable the development of energy-efficient machine elements with lubricated contacts, an exact calculation of the existing thermo-elastohydrodynamic (TEHD) contacts is necessary for the design, taking into account the deviations from production.Extensive, analytically solvable approximations for the calculation of lubrication film and pressure parameters for infinite line and three-dimensional point contacts already exist. However, these do not take sufficiently into account manufacturing deviations that occur in every component. At the same time, there are reliable but time-consuming simulation tools for TEHD contact calculation. In the context of the product development process and when used in multi-body or system simulations, however, a simple and time-efficient application is an essential requirement for the used calculation model.Due to missing approximations for the exact calculation of deviated contacts, the aim of the planned research project is the development of predictive models for the determination of the central and minimum lubrication film thickness as well as the maximum pressure and temperature in concentrated contacts under consideration of surface deviations. For this purpose, wave-shaped deviations of the surface are parametrically integrated into TEHD simulation models for the infinite two-dimensional line contact as well as the three-dimensional point contact. Using the chair's own TEHD simulation tool, TriboFEM, these two models are analyzed to determine the effects on the formation of the lubricant film and the distribution of pressure in the contact and to generate a database. Based on this database, predictive models for the infinite line and three-dimensional point contact are developed by introducing an additional correction factor to the approximations of DOWSON/HIGGINSON or BLOK/MOES, by more complex methods such as mathematical regression and modern methods of machine learning. By evaluating the prediction models on criteria such as accuracy, usability and time efficiency, a suitable prediction model is selected for line and point contact. At the end of this research project, an application example will be used to demonstrate its applicability in product development.