scholarly journals The Application of Ultrasonic NDT Techniques in Tribology

2005 ◽  
Vol 219 (5) ◽  
pp. 347-366 ◽  
Author(s):  
R. S. Dwyer-Joyce
Keyword(s):  
Rough Surface ◽  
Ultrasonic Waves ◽  
Current State ◽  
Surface Contact ◽  
Machine Elements ◽  
Lubricated Contact ◽  
Rough Surface Contact ◽  
Ultrasonic Ndt

The use of ultrasonic reflection is emerging as a technique for studying tribological contacts. Ultrasonic waves can be transmitted non-destructively through machine components and their behaviour at an interface describes the characteristics of that contact. This paper is a review of the current state of understanding of the mechanisms of ultrasonic reflection at interfaces, and how this has been used to investigate the processes of dry rough surface contact and lubricated contact. The review extends to cover how ultrasound has been used to study the tribological function of certain engineering machine elements.

Lubrication of Rough Surfaces by a Boundary Film-Forming Viscosity Modifier Additive

2005 ◽  
Vol 127 (1) ◽  
pp. 223-229 ◽  
Author(s):  
R. P. Glovnea ◽  
A. V. Olver ◽  
H. A. Spikes
Keyword(s):  
Rough Surface ◽  
Rough Surfaces ◽  
Viscosity Index ◽  
Functionalized Polymers ◽  
Contact Conditions ◽  
Film Forming ◽  
Boundary Film ◽  
Surface Contact ◽  
Lubricated Contact ◽  
Rough Surface Contact

In previous work it was shown that some functionalized polymers used as viscosity index improvers are able to form thick boundary lubricating films. This behavior results from adsorption of the polymer on metal surfaces to form a layer of enhanced viscosity adjacent to the surface. In the current work the behavior of one such polymer in rough surface contact conditions is studied, using both model and real rough surfaces. It is found that the polymer is able to form a thick boundary film in rough surface contact, just as it does with smooth surfaces. It is also shown that the effect of this boundary film is to significantly reduce friction in rolling-sliding, rough surface, lubricated contact.

Rough Surface Normal Nanocontact Stiffness: Experimental Measurements and Rough Surface Contact Model Predictions

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Jungkyu Lee ◽  
Ali Beheshti ◽  
Andreas A. Polycarpou
Keyword(s):  
Thin Film ◽  
Rough Surface ◽  
Predictive Accuracy ◽  
Contact Stiffness ◽  
Flat Punch ◽  
Surface Contact ◽  
Contact Models ◽  
Rough Surface Contact ◽  
Contact Response ◽  
Good Agreement

This work presents experimental contact stiffness measurements for various thin films as well as homogenous materials through pressing a flat punch onto a nominally flat rough surface. These materials are typically used in micro/nano technological applications with thickness of the order of few nanometers. The experimental contact stiffness results are compared with predictions by different statistical rough surface contact models to assess their predictive accuracy for thin-film applications and, in addition, to get better insight to the physics of the contact. It is observed that rough surface contact models that account for asperity interaction show good agreement with the experimental results of the thin-layered specimens contact response. This indicates the importance of accounting for asperity interaction in surface roughness contact modeling of relatively smooth thin-film materials. It is verified that interfaces with compliant films on stiff substrates as well as homogeneous materials compare relatively well with statistical models accounting for asperity interactions.

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