Vorhersage der geometrischen Oberflächenveränderung im Wälzkontakt

  • Prediction of the geometrical surface changes in rolling-sliding contacts

Mevissen, Dieter Johannes Wilhelm; Brecher, Christian (Thesis advisor); Sauer, Bernd (Thesis advisor)

1. Auflage. - Aachen : Apprimus Verlag (2021)
Book, Dissertation / PhD Thesis

In: Ergebnisse aus der Produktionstechnik 23/2021
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2021

Abstract

The surface roughness and structure of rolling-sliding contacts have a decisive in-fluence on the running behavior in terms of friction, wear and fatigue. Due to runningin effects, there is a continuous change of the surface roughness during the first load cycles. In general, however, only the surface condition after the final manufacturing process is known to evaluate the performance. The knowledge of the surface properties after runningin enables a more precise analysis and a deeper un-derstanding of the function of the rolling sliding contact from a scientific point of view. From an economic point of view, an early assessment of production related surfaces with regard to running behavior is desirable in order to avoid exaggerated safety factors and to reduce testing costs.For this reason, the aim of this work was a calculation method to predict the geomet-ric surface change in rolling-sliding contacts. Based on the calculation method, the gap between the production-related surface and the surface topography after the running in which is relevant for the performance during operation can be closed already during the design process. The scientific originality is characterized by a large scale micro contact calculation, which forms the basis for a connection between micro and macro levels. Contrary to the state of the art, the main model for calculating lubricated, rough rolling-sliding contacts was anchored on the micro level and existing knowledge on the influence of hydrodynamics on the macro level was integrated through simplified maps. The influence of the lubricant pressure was implemented by a lubricant boundary condition for the contact calculation in the elastic half space according to BOUSSINESQ, LOVE and HARTNETT. In order to achieve the overall goal, basic experimental tests with the focus on the geometric surface changes during running-in were carried out on a disk-on-disk test rig. The investigations comprise tests with and without lubrication for pure rolling conditions as well as tests under sliding conditions. In particular, the test program built the basis for a step-by-step validation of the calculation method. For the operat-ing conditions investigated, the geometric surface change during running-in can be primarily reduced to the mechanism of plastic deformation. The change of single roughness peaks as a result of the loaded contact could be quantified by a high precision comparison of surface topographies before and after the experiment. The experimental tests were used for a stringent validation of the developed calculation method.

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