An Analytical Model of Mechanistic Wear of Polymers

Abstract

This paper proposes a wear model for polymers based on so-called mechanistic processes comprising both low cycle fatigue and abrasive wear mechanisms, which are prominent in polymer–metal sliding interfaces. Repeated elastic contact causes localized fatigue, whereas abrasive part is an anticipatory outcome of plastic contacts by hard metal asperities on to soft polymer surface. Further, presuming adhesive interactions in elastic–plastic contacts, asperity contact theories with necessary modifications were analyzed to assess load and separation for their subsequent use in elementary wear correlations. Both Gaussian and Weibull distributions of asperity heights were considered to include statistics of surface microgeometry. Finally, volumetric wear was written in terms of roughness parameters, material properties, and sliding distance. Validation was conducted extensively, and reliability of the formulation was achieved to a large extent. Experimental part of this work included several pin-on-disk tests using polyether ether ketone (PEEK) pins and 316L stainless steel disks. Disks with different roughness characteristics generated by polishing, turning, and milling were tested. Experimental results agreed well with predictions for the polished surface and with some deviations for other two surfaces. Further, fatigue to abrasive wear ratio was identified as an analytical tool to predict prevailing wear mechanism for polymer-metal tribo-systems. After examining the considered cases, it was both interesting and physically intuitive to observe a complete changeover in wear mechanisms following simply an alteration of roughness characteristics.

A review of recent advances in tribology

“…Based on the observations of evolutions of wear rate, worn surface morphology, transfer film, and debris morphology, the authors identified three wear stages, initial wear stage, severe wear transition stage, and ultralow stable wear stage. Panda et al [223] proposed an analytical model for prediction of mechanistic wear of polymer materials. The model is derived on the assumptions of abrasive wear and fatigue wear, and validation experiments with PEEK, PMMA, and PVC against 316L stainless steel were performed.…”

Correlation of Tribological Behavior and Fatigue Properties of Filled and Unfilled TPUs

“…In this study, two wear models were applied to correlate the wear behavior and fatigue properties. The first model, developed by Panda [10], is based on abrasive and fatigue wear mechanisms. In Panda's model, the surface roughness of the counter surface is taken into consideration.…”

“…In Panda's model, wear is partly due to the fatigue wear mechanism, which is purely caused by elastic contacts, while the other part is from the abrasive mechanism under plastic contacts [10,12]. The model is based on the micro-mechanistic deformation at the asperity scale.…”

“…The asperities on a rough surface are rigid and show a spherical tip; they follow a probability distribution. In addition, abrasive wear only results from plastic contacts of asperities, while only elastic contacts lead to fatigue wear [10]. The filler effect, specimen roughness, and thermal influence are beyond the scope of this model.…”

Investigations on Contact Pressures and Durability of Metal-Polymer Dry Sliding Bearings with Miniature, Small and Large Diameters

“…The friction and wear of the PTFE + 25Bronze composite (bronze powder) were studied in a similar way [7]. Some experimental results on tribological behavior of highly efficient polymers under friction on steel are presented in [8][9][10][11][12]. Wear of REEK under dry friction on steel according to the scheme of end friction is established in [8].…”