When a wave of ultrasound strikes an interface between two bodies some proportion of the wave amplitude is reflected. A rough surface interface with a low real area of contact will reflect more ultrasound. This is the case for both normal and shear modes of ultrasound. If the ‘gaps’ in the contact are filled with liquid, then more of a longitudinal wave is transmitted through the interface. However, the shear wave should remain unaffected, since it is virtually all reflected at a solid liquid boundary. It is the stiffness of the interface that controls the response. Measurements of reflection can readily be used to determine the interface stiffness. In this work a series of experiments has been performed to measure the reflection of both normal and shear ultrasound from both dry and wet rough contacts. This gives information about the normal and shear stiffness of dry contacts. When the layer is flooded with a liquid the stiffness of the liquid part alone can be deduced. This can be used to determine the film thickness in mixed lubrication. The shear stiffness was found to reduce with the application of a liquid; this is caused by the presence of asperity micro-slip at the interface.
Shear and Normal Stiffness of Mixed Liquid-Solid Contacts
- Views Icon Views
- Share Icon Share
- Search Site
Dwyer-Joyce, RS, & Gonzalez Valadez, M. "Shear and Normal Stiffness of Mixed Liquid-Solid Contacts." Proceedings of the World Tribology Congress III. World Tribology Congress III, Volume 1. Washington, D.C., USA. September 12–16, 2005. pp. 349-350. ASME. https://doi.org/10.1115/WTC2005-63793
Download citation file: