Numerische und versuchstechnische Bewertung von tribologischen Kontakten

Translated title of the contribution: Numerical and experimental assessment of tribological contacts

Research output: ThesisMaster's Thesis


Due to increasing environmental requirements OEM's are forced to a more efficient conversion of fossil fuels. In order to achieve these demands fuel saving technologies such as start-stop and hybrid are gaining in importance. For bearings in the engine follow problematic operating conditions. Since the mixed friction area is traversed more often, friction and wear is increased over the entire operating time. To counteract these losses, further developments in microstructures of surfaces, materials and supplies are required supported by tribological simulations. For these the solid contact is taken into account by means of contact models. In the course of this thesis three different approaches are used to describe contact. These include the use of popular statistical models, conducting experiments and numerical investigations. Purpose of viewing these methods is the consideration of each necessary expense to the results obtained and a comparison with each other. The first approach is the evaluation of five statistical models including Greenwood-Williamson (GW), Chang-Etsion-Bogy (CEB), Zhao-Maietta-Chang (ZMC), Kogut-Etsion (KE) and Jackson-Green (JG). For the analysis of the different models, journal bearing shells are used with different materials and surfaces. To obtain the required parameters, surface surveys and indentations must be performed. The evaluation is carried out by a self developed Matlab® routine. In order to show the behaviour in solid contact of conventional shaft bearings pairings, a new test method is used. The aim is to build a new experimental arrangement for the existing sample geometries. For the purposes of this test, the hardness testing machine 2.5 ZHU from Zwick-Roell is used. In addition, the contact conditions between journal bearing and shaft surfaces are determined by using ABAQUS® simulations. Here a mesh is created in Hypermesh® based on surface measurement data and implemented into the fem-software. In order to keep the computational complexity low, a dimension reduction by creating a 2D form a 3D model is performed. The aim of these methods is to investigate the behaviour of the contact pressure on the deformation of surfaces. The contact models show that the contact pressure has greater differences among each other than the courses of the contact area. Also the contact models differed from each other at the same geometry due to the weight of parameters. Thus, the contact pressure of the GW-model increases to a 50 per cent higher level compared with the other models due to the purely elastic viewing. Also the area increases less with the GW-model at the same pressure rise. As is apparent from the results of the contact models and the simulation results, there is an influence of the different materials in priority to the surface roughness with larger deformations. The experimental results show differences between the bearing shell types. This can’t be considered absolutely due to systematic errors (e.g. machine stiffness). The result is contact data from the new experimental setup and the knowledge for the further development of the testing methods. A comparison of the methods illustrates on the one hand the strong deviation of the experimental data to the simulation and the contact model data, and on the other hand that the simulation and contact models provide comparable results.
Translated title of the contributionNumerical and experimental assessment of tribological contacts
Original languageGerman
  • Bergmann, Philipp, Co-Supervisor (internal)
  • Godor, Istvan, Co-Supervisor (internal)
  • Grün, Florian, Supervisor (internal)
Award date1 Jul 2016
Publication statusPublished - 2016

Bibliographical note

embargoed until 18-05-2019


  • tribology
  • contact mechanics
  • contact models
  • rough surface
  • real contact area
  • contact pressure

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