Shear adhesion, friction, and wear of multi-point micro- and nano-scale contacts
Abstract/Contents
- Abstract
- Adhesion, friction, and wear are the principal failure mechanisms that have limited the use of contacting and sliding surfaces in commercial MEMS applications. As the size of mechanical structures reaches the micro- and nano-scales, surface forces such as van der Waals, capillary, and electrostatic forces dominate the interactions between contacting surfaces. At these scales, the magnitude of the friction force is very sensitive to the complicated interaction between the surface properties, material properties, contact conditions, and environmental conditions. This work investigates the role of the contact conditions on the friction forces and wear rate of a MEMS probe array of small-scale tips in contact with a flat sliding surface. The friction measurement experiment involves a laterally unconstrained slider that sits on top of a MEMS probe array. As the array is laterally actuated, solely friction forces at the tips govern the motion of the slider. MEMS probe arrays enable precise control over the shape and the total number of contact points between the two surfaces. The results show that the friction forces are very sensitive to small changes in the contact or environment conditions. But for a given, well-controlled set of conditions, the friction forces scale linearly with the normal force. However, the friction coefficient is strongly dependent on the total number of contact points and the local conditions around those contact points. Factors such as humidity or adsorbed water on the surfaces further increase the linear relationship between the friction forces and the number of contacts. In addition, the wear rate of the tips is linearly related to the normal force acting at each tip. Factors such as the presence of water on the surface and a stiff vertical contact also lead to high wear rates. This work concludes with a set of recommendations to minimize the detrimental effects of friction and wear at the micro- and nano-scales.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2010 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Smith, Wesley Scott |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Kenny, Thomas William |
| Thesis advisor | Kenny, Thomas William |
| Thesis advisor | Hartwell, Peter George, 1971- |
| Thesis advisor | Howe, Roger Thomas |
| Advisor | Hartwell, Peter George, 1971- |
| Advisor | Howe, Roger Thomas |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Wesley Scott Smith. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2010. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2010 by Wesley Scott Smith
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...