Friction and Wear: From Elementary Mechanisms to Macroscopic Behavior

In the last 25 years, the global trend to miniaturization has raised interest in frictional processes on the micro and nano scale and facilitated appearance of nanotribology as a new branch of research. Soon it became clear that looking at tribological processes at micro- and...Read More »


Green Tribology

Tribology is Integral to Global Energy Consumption, Costs and Emissions

Three principle industries in today’s society are transportation, power generation, and manufacturing. All three industries involve machines of all types, with moving parts subject to friction and wear, and therefore rely on tribology to help...Read More »


Creating a Robo-Dog Army: Tribological Aspects

Recently Boston Dynamics’ released a video of a robo-dog army pulling a truck down the road. The future is here. For now it looks like the good old Terminator I movie. But I guess...Read More »


Tribology of Earthquakes

Earthquakes are the sudden shaking of the ground caused by seismic waves passing through Earth’s rocks. These seismic waves occur when energy stored in the Earth’s crust is released suddenly, typically when large masses of rock pushing against each other suddenly break and slip. Typically, these occur along...Read More »


Should the contact area really increase due to sliding, and why this is never observed?

Abstract

A paper by Menga, Carbone & Dini (MCD) recently published in prestigeous journal, suggests that in the contact with adhesion, the effect of tangential forces, and in particular of shear stresses assumed constant at the interface and equal to a material constant, an increase of contact...Read More »


Tribology and the Human Evolution

Tribology, not a common household word, is the science of wear, friction, and lubrication, studying how interacting surfaces behave in relative motion. Tribology does not work in isolation but affects a multitude of other fields including, but not limited to, mechanical engineering, manufacturing, chemical engineering,...Read More »


NASCAR Pile Up and Importance of Friction

A real life examples to help explain the importance of tribology are priceless. Car races can provide an exciting example. A pile...Read More »


Friction in Only One Direction

Nature has amazed us since the beginning of time. It provides the foundation for all of our best ideas. The animal world provides the inspiration behind one of the new inventions in the world of tribology – namely microstructured material designed with spatial variation to create one...Read More »


Fracture Physics and Crack Propagation

Fracture physics, a field of study in materials science, works on understanding how and why things break by quantifying and analyzing fracture surface topography. Scientists can reconstruct the history of a crack and determine the conditions that led to the initial formation of said crack. Preventing fractures is...Read More »


Leonardo da Vinci as a Tribologist

Tribology is the science dealing with interactive surfaces in relative motion and includes the study of friction, wear, and lubrication and how these properties affect design. The term tribology was coined in 1966 by Peter Jost, the man considered the founder of tribology. Leonardo da Vinci...Read More »


Tribology and Electric Vehicles

Electric Vehicles Through the Years

Electric vehicles, while often considered a new phenomenon, have existed since the 1800s. At that point in time, electric vehicles outnumbered gasoline powered vehicles for many reasons. Electric vehicles did not have the same vibration, noise, and smell of gasoline-powered cars....Read More »


Tracking a Sudden Fail of Microelectormechanical Systems

What time does it take before the minute parts of microscopic equipment become unusable as a result of deterioration? What warning signals do you need to watch out for that will show that the components will soon fail to function as required? In a bid to provide swift...Read More »


Phase-Switching Liquids Frost 300 Times Longer Compared to Known Anti-Icing Coatings

Ice and frost formation on surfaces afflicts various energy and transportation industries worldwide, causing economic losses in billions of dollars annually. Most techniques to prevent frost and ice formation on surfaces rely heavily on heating or liquid chemicals that need to be reapplied over and over again because...Read More »

Tribometer managing autumn leaf problem on railways worldwide

Since the 1800s, railway organizations have been struggling with low adhesion on the rail, especially during the Autumn season also known as the “slippery track season”. In Autumn, leaves fall on the rails and when train wheels crush the leaves, they become a layer of oil...Read More »


How can tribology help extend critical machinery service life?

Tribology is the science of interacting surfaces in relative motion. Basically, it studies friction, wear and lubrication – three phenomena linked to surface degradation and, thus, to machine reliability and performance. When machines wear out, they perform worse, are less productive and, finally, begin...Read More »


Guidance Notes on Friction

In dry sliding between a given pair of materials under steady conditions, the coefficient of friction may be almost constant. This is the basis for two EMPIRICAL Laws of Sliding Friction, which are often known as Amontons’ Laws and date from 1699. They are in fact not...Read More »


Contact Mechanics Book

The Handbook on Contact Mechanics (Handbuch der Kontaktmechanik) co-authored by Honorary Professor of Tomsk Polytechnic University, head of the Department of System Dynamics and Friction Physics at Technical University Berlin, Valentin Popov, a TPU alumnus Emanuel Willert, and Assistant Professor of the Department of System Dynamics and...Read More »


On the history of elastohydrodynamics

Here we present an abstract to a paper devoted to the history of eastohydrodynamic theory and his founder – Alexander Mohrenstein-Ertel. This paper discusses in detailes the peculiar biography of the scientist and the early years of the theory development.

On the history of elastohydrodynamics: The dramatic destiny of Alexander...Read More »


Note on the history of contact mechanics and friction

No future without history! A great article on the history of great discoveries in the field of contact mechanics and friction was recently published by Elena Popova and Valentin L. Popov. Here we present the abstract of the article.

Abstract

Great discoveries are often perceived by subsequent generations as sudden...Read More »


The correct lubricant: a practical guide to choose lubricating oil

‘The correct lubricant’ covers basic practical information about lubricants in automotive and industrial areas. It is written for users of lubricants, giving only what is essential to know and useful for them. It could also be used by professionals in the field who must explain various aspects of...Read More »


Impact of water on Grease film thickness in rolling point contacts

In a rolling bearing, the load transmission is often accompanied by high contact stresses which may eventually lead to wear and/or fatigue. In order to ensure separation of moving parts leading to a long life, bearings are usually grease or oil lubricated. The separation of the moving parts in a...Read More »


After the Mystery of Rotary Lip Seals

Lip seals compete with mechanical face seals in sealing oil or grease in rotary shaft applications. Under certain running conditions both kinds of seals can be used however, the latter ones are generally used for applications where a significant pressure difference needs to be preserved. Rotary lip seals are preferred...Read More »


Friction is a possible reason for SpaceX Falcon 9 explosion

September 1 of 2016 at Cape Canaveral SpaceX lost is Falcon 9 rocket on a launch pad due to dramatic explosion. During a routine preflight fueling test, the  rocket and the $200 million Israeli Earth communication satellite Amos-6 were lost. No one was injured.

A...Read More »


What contributes to thicker grease films ?

A rolling bearing preferably runs under EHL conditions. The film thickness between the rolling elements and the rings is determined by the lubricant properties, operating conditions and bearing design. During the initial phase of operation, macroscopic flow (churning) of the grease takes place. It is usually during this churning phase...Read More »


Argonne Embraces Concept of "in operando" Formation of Carbon-based Tribofilms

Earlier this month, tribologists and physicists at the U.S. Department of Energy (DOE) Argonne National Laboratory published news of their (self-described) “self-healing diamond-like carbon coating [that] could revolutionize lubrication” in the journal Nature.  The researchers claim...Read More »


Contact Area vs. Load: Simple Scaling Laws

“God made the bulk; surfaces were invented by the devil”, a Nobel prize winning physicist Wolfgang Ernst Pauli said. In tribology, as in many other sciences, surface features (asperities, roughness) play an important role. In many cases, the surface roughness dramatically alters the friction, contact area,...Read More »


Small Particles - Big Problems

Tiny particles are all over around us and sometimes they may create problems. This is especially of concern with metal particles formed due to wear in man-made engineering devices. Particles formed in car disk brakes may harm lung cells, metal particulate limits the service life of artificial hip...Read More »


Determining Fatigue Wear Using Wear Particle Analysis Tools

...Read More »

Nordtrib 2016: conference summary and outlook on the field of tribology 50 years after the Jost report

Nordtrib 2016 came to a close last Friday and I returned home inspired and energized for the next stint in my PhD research. This post is an overview of the conference and summarises the outlook on the field for the years to come based on the round table discussions and...Read More »


Who is The First? Leonardo da Vinci!

Leonardo di ser Piero da Vinci, the famous Italian engineer, architect, painter, musician, mathematician can also be considered as The First Tribologist! Although the term itself was invented approximately 450 years after Leonardo da Vinci (1452-1519), he was the first one to perform the systematic study on friction,...Read More »


Bio-lubricants and Environmentally Acceptable Lubricants (EAL)

The increasing awareness on environmental pollution caused by many chemicals, including lubricants, promotes the use of environmentally friendly products. There is a clear trend towards a more responsible use of lubricants and several legislations already limit the use of certain oils in some applications. Bio-lubricants are present in construction, mining...Read More »


In Situ Nanopolishing (ISN): A New Lubrication Paradigm Aimed at Permanent Surface Perfection

All conventional lubricants borne of classic hydrodynamic theory are designed to provide lubricity. Inherent in the desire to provide lubricity to mechanical systems is the desire to protect the interacting metal surfaces from wear. Much effort in tribology...Read More »


Surface Replication Compounds

The first challenge when measuring a surface topography via optical techniques is getting the sample to the lab. Although optical surface roughness measurement does not damage the component per se (NDT), the fact of fitting it into a microscope generally requires the destruction of the original component. The surface replication...Read More »


Wear in nanoscale: optimum AFM tip roughness

Wear is a gradual removal of the material of the bodies during their interaction. The process appears in many mechanical systems, ranging from large scales, as in wind mills, to nanoscales, as in the AFM tip – substrate contact. The macroscale wear is a relatively well developed field of tribology,...Read More »


"Car 2020" and Tribology Research

Friction has been a challenge for the mankind throughout the whole history since it resists the motion. It resists the transportation of goods. And transportation shares 20% of the global energy consumption and approximately 18% of the greenhouse gas emissions. Out of this share, road transportation builds up to 72%...Read More »


Ice Lubrication and the Forbidden City

Forbidden City is a historical symbol of China, located in the center of Beijing and was constructed between 1406 and 1420 . It served as an imperial palace for almost 500 years and consists of 980 buildings on 180 acres area. Large number of massive buildings required mining and transportation...Read More »


So, what is it, superlubricity?

From the first friction quantitative experiments by Leonardo da Vinci (1452-1519) and most notably from our everyday life experience, it is known that there is an inevitable force opposing to the initiation of motion of one body on the surface of another. This force has to be exceeded, in order...Read More »


Modeling rough adhesive surfaces

Imagine a new type of tyres whose structure has been designed to have greater adhesion on the road. Quite a timely discussion during the long winter nights. French physicists have now developed a model to study the importance of adhesion in establishing contact between two patterned, yet elastic, surfaces. Nature...Read More »


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