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Lecture

Consequences of surface texturing on third body flows during fretting tests

Thursday (27.09.2018)
14:45 - 15:00 S1/01 - A5
Part of:


Fretting wear damages are observed in numerous contacts subjected to vibrations. These wear damages can be very detrimental in many industrial applications. Unfortunately no fretting wear model is currently able to provide reliable predictions. The actual strategy consists in applying the Archard’s wear equation. This simple approach does not consider the effect of debris layer (third body) entrapped between the 2 first bodies in contact, whereas it plays a critical role. When the particles flow in the contact, under mechanical action they create fresh surfaces on which the physical-chemistry of the environment will or will not “have time” to react. Consequently the particles can more or less be reconstituted, agglomerated, oxidized, and/or adhered to the first bodies. The wear rate is defined through a balance between the debris formation flow and the debris ejection flow from the contact.

A customized tribometer [1] is used to perform fretting wear tests (pin on flat geometry, steel), in the aim to investigate how texturing a surface could control the third body flow evacuation and third body thickness. Post-mortem analysis are performed to estimate the third body thickness and its morphologies (compaction, orientation, anisotropy, size of the particles) through different analytical tools (such as SEM, AFM). At the same time, a discrete approach is used to model the third body flows and to describe the evolution of such discontinuous medium. The third body is modelled using a numerical framework [2]: a multibody meshfree model allows to take into account the heterogeneity of third bodies composed of the deformable grains with a user-defined constitutive behavior, accounting for the possibly complex adhesive interactions between the particles and between those and the first bodies. Different profiles of the first bodies surface are investigated. A coupling between experiments and modelling are built through the global measurements (forces) and the post mortem characterizations at a submicronic scale.

[1] Y. Zhang et al, J. Th. Spray Technol 25, 2016

[2] G. Mollon, Tribology International 90, 2015

Speaker:
Dr. Sylvie Descartes
Université de Lyon
Additional Authors:
  • Dr. Guilhem Mollon
    Université de Lyon
  • Dr. Yinyin Zhang
    Université de Lyon