Video of fretting wear occuring between a sapphire and flat

This is a video of fretting occurring in an unlubricated contact.  One body is a steel ball and the other is a sapphire flat.  The camera is viewing the contact from above through the sapphire, so the circle in the center of the screen is the outline of the Hertzian contact. Wear initiates at the [...]

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Video of lubricated fretting contact

This is a high speed video of fretting occurring in a grease lubricated contact.  One body is a steel ball and the other is a sapphire flat.  The camera is viewing the contact from above through the sapphire, so the circle in the center of the screen is the outline of the Hertzian contact. The [...]

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Finite element fretting wear modeling of a three-dimensional spline coupling

In most studies finite element fretting models have been used to analyze two-dimensional contacts.  However, as processing power becomes less expensive, we can expect that three-dimensional models will become the norm.  The finite element method has already been used for three dimensional fretting wear analysis with Abaqus. One reason for using three dimensional analysis is [...]

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Lamellar solid lubricants: graphite and molybdenum disulfphide

Lamellar solids are frequently used as solid lubricants.  Two of the most commonly used and effective lamellar structured solid lubricants are graphite and molybdenum disulphide.  Scientists are unclear why these two materials perform better than other lamellar materials, but most research is still directed towards them because of their tribological qualities. Both materials have strong [...]

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Solid Lubricants: why to use them and why they work

Solid lubricants are frequently used as fretting palliatives.  One of the more common solid lubricants is molybdenum disulfide (MoS2).  There are several reasons why solid lubricants are used instead of liquid (oil) or semi-solid (grease) lubricants. Cleanliness: there is no need to deal with oil getting on equipment Lubricant supply: generally solid lubricants are applied [...]

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Modeling Fretting Wear of W-DLC Coatings Using Abaqus

A.L. Mohd Tobi and colleagues at the University of Nottingham published an article describing how to model fretting wear of materials protected by a diamond-like-carbon coating.  They used Abaqus to perform their analysis as well as experimental tests for validation. Diamond-Like-Carbon coatings or DLC coatings are made from carbon.  They are referred to as diamond-like [...]

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Hardness and fretting wear

Fretting wear is frequently modeled using the Archard equation.  The primary reason for this is that the equation is widely used and it is easy to determine the input variables.  Unfortunately, the equation does not match well with experimental data about fretting.  One discrepancy between the fretting phenomenon and Archard theory is commonly discussed:  the [...]

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The effect of oil lubrication on fretting wear

Lubricants can be used to reduce fretting wear, but they will generally not eliminate the problem entirely.  This is because the velocities in a fretting contact are low and motion is intermittent.  As a consequence a full lubricant film cannot form in a fretting contact. One option is to stop the fretting motion entirely.  If [...]

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The effect of high temperatures on oxidation and fretting wear

The temperature level can play a large role in fretting.  High temperatures generally affect the fretting phenomenon through one of three mechanisms: Changing the rate of corrosion Changing the rate of oxidation Altering material mechanical properties Of these three factors, oxidation is believed to be the most important.  High temperatures induce oxide films to form [...]

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Crystal plasticity simulation videos

The Dusseldorf Max-Planck group and SUNY has made some interesting videos about crystal plasticity.  While this is not directly related to fretting, it is an area of interest to the engineering community as a whole.  For some introductory information about crystal plasticity, you can read this introductory article from the University of Edinburgh. Experimental Time [...]

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