A very interesting wear theory by Persson and coworkers has been recently proposed (in fact, it is still under review!).
I make some comments and simplifications here to show general trends
https://www.researchgate.net/publication/387143610_Some_comments_on_a_r…
Wear is a complex problem, and I don't think this theory will give easily quantatitative predictions, but it certainly deserves attention.
My abstract follows
Ernest Rabinowicz’s words, spoken two decades ago in his groundbreaking textbook on the friction and wear of materials [1], continue to resonate today: ’Although wear is an important topic, it has never received the attention it deserves.’ Rabinowicz’s work laid the foundation for contemporary tribology research [2]. Wear, characterized as the removal and deformation of material on a surface due to the mechanical action of another surface, carries significant consequences for the economy, sustainability, and poses health hazards through the emission of small particles. According to some estimates [1, 3], the economic impact is substantial, accounting for approximately 5% of the Gross National Product (GNP).
Despite its paramount importance, scientists and engineers often shy away from wear analysis due to the intricate nature of the underlying processes. Wear is often perceived as a ”dirty” topic, and with good reason. It manifests in various forms, each with its own intricacies, arising from complex chemical and physical processes. These processes unfold at different stages, creating a time-dependent phenomenon influenced by key parameters such as sliding velocity, ambient or local temperature, mechanical loads, and chemical reactions in the presence of foreign atoms or humidity.
The review paper by Vakis et al. [5] provides a broad perspective on the complexity of tribology problems. This complexity has led to numerous isolated studies focusing on specific wear mechanisms or processes. The proliferation of empirical wear models in engineering has resulted in an abundance of model variables and fit coefficients [6], attempting to capture the intricacies of experimental data.
Tribology faces a fundamental challenge due to the multitude of interconnected scales. Surfaces exhibit roughness with asperities occurring at various wavelengths. Only a small fraction of these asperities come into contact, and an even smaller fraction produces wear debris. The reasons behind why, how, and when this occurs are not fully understood. The debris gradually alter the surface profile and interacts with one another, either being evacuated from the contact interface or gripping it, leading to severe wear. Due to this challenge of scales, contributions of numerical studies in wear research over the past decades sum up to less than 1% (see Fig. 1). Yet, exciting opportunities exist for modeling, which we attempt to discuss here.
While analyzing a single asperity contact may not unveil the entire story, it arguably represents the most fundamental level to comprehend wear processes. This blog entry seeks to encapsulate the authors’ perspective on this rapidly evolving topic. Acknowledging its inherent bias, the aim is to spark controversies and discussions that contribute to a vibrant blogosphere on the mechanics of the process.
The subsequent section delves into the authors’ endeavors in modeling adhesive wear at the asperity level. Section 3 navigates the transition to abrasive wear, while Section 4 explores opportunities for upscaling asperity-level mechanisms to the meso-scale, with the aspiration of constructing predictive models. Lastly, although the primary focus of this blog entry is on modeling efforts, it would be remiss not to mention a few recent advances on the experimental front.
Abstract submission system now open!
23rd International Conference on Wear of Materials, Banff, Alberta, Canada from 25-29 April 2021.
The School of Engineering and Applied Science at the University of Pennsylvania invites applications for two full-time Postdoctoral Researcher positions in the laboratories of Prof. D.S. Srolovitz (https://www.seas.upenn.edu/directory/profile.php?ID=180) and Prof. Robert W. Carpick (http://carpick.seas.upenn.edu).
An interesting paper by VL Popov which suggests many problems of tribology are still very far from being remotely solved. Despite the very detailed theories for example on rough contact using fractal surfaces on which we have debated mainly academically , there is not a single theory for any quantitative prediction of friction coefficient which can vary by 1 order of magnitude and its dependence on many variables, let alone wear coefficient which can vary up to 7 orders of magnitude. What is left to do, other than measure? Is tribology bound to be in practice just an
Friction and wear are important processes that determine the function of many mechanical devices, but their underlying microscopic physical principles are complex and often not well understood. Amorphous – or glassy – materials often form on surfaces that have experienced frictional loading. The research will involve large-scale molecular dynamics simulation of the near-surface deformation upon indentation and scratching of network and bulk metallic glasses.
The 20th International Conference on Wear of Materials will focus on both the fundamental and applied aspects of wear and friction of materials at the macro-, micro-, and nano-scale. It will address the understanding of tribological phenomena; particularly the progress in recent decades and a special session will concentrate on modeling of wear.
10 days to go before the conference starts. Check out the latest program from the conference website http://www.wearofmaterialsconference.com and don't forget to register if you are planning to attend.
Wom 2013 keynote speakers and their topics have been announced:
Dr Ali Erdemir
Argonne National Laboratories, USA
Innovative surface engineering strategies for mitigating wear of materials under extreme conditions
Dr Michael Moseler
FhG-IWM Freiburg, Germany
Atomistic understanding of wear in carbon tribomaterials
