Featured Research

from universities, journals, and other organizations

Friction: All may look smooth, but there are 'bumps' along the way

Date:
March 9, 2010
Source:
The Hebrew University of Jerusalem
Summary:
Friction in human relations is all too obvious and prevalent, but friction in physics has had a "secret life" of its own that has now been revealed by scientists.

Friction in human relations is all too obvious and prevalent, but friction in physics has had a "secret life" of its own that has now been revealed by scientists at the Hebrew University of Jerusalem.

In an article appearing in the journal Nature (with a further reference to it in Nature Physics), the scientists show how frictional strength evolves from extremely short to long time scales. The new information could be useful in assessing a wide range of natural and man-made phenomena -- from earthquakes to computer hard drives

"Although friction plays such an important role in so many aspects of our lives, it is surprising that many key processes embodied within frictional motion have been far from understood," said Jay Fineberg, the Max Born Professor of Natural Philosophy at the Hebrew University and author of the Nature article along with Ph.D. students Oded Ben-David and Shmuel Rubinstein.

Fineberg said that while frictional motion is often thought of as the motion of two bodies against each other, separated by a perfectly smooth plane, in fact, due to the microscopic roughness of sliding surfaces, all of the contact between sliding bodies takes place in only a tiny area. Thus, only a sparsely spaced microscopic "bumps" are responsible for maintaining the contact between two sliding bodies. It is the behavior of these bumps which governs friction.

These microscopic contacts have a life of their own that very much differs from that of bulk materials, commented Fineberg. It is that "secret life" that has now been described in the research of the Hebrew University researchers. Their study shows how frictional strength evolves from extremely short to long time scales.

Millionths of seconds before bodies start to slide against one another, a miniature "earthquake" tears through the interface and ruptures the contacts, said Fineberg. From that moment of contact rupture, four distinct and interrelated phases of evolution are identified, he said. These include the violent rupture phase, resultant contact weakening, and continuing through renewal and re-strengthening. These results provide a comprehensive picture of how frictional strength evolves.

Fineberg emphasized that a fundamental understanding of these processes is critical to a variety of important problems and applications, such as the evolution of frictional strength at short-time impacts as in, for example, the read/write cycle of hard drives, frictional dissipation in an internal combustion engine, and the dynamics of earthquakes.

At the other end of the spectrum, long-time strengthening processes are critical when considering the need for strengthening a fault or frictional interface. This understanding could lead the way to manipulation and control of such dynamics, at small and large scales alike, he said.


Story Source:

The above story is based on materials provided by The Hebrew University of Jerusalem. Note: Materials may be edited for content and length.


Cite This Page:

The Hebrew University of Jerusalem. "Friction: All may look smooth, but there are 'bumps' along the way." ScienceDaily. ScienceDaily, 9 March 2010. <www.sciencedaily.com/releases/2010/03/100308095501.htm>.
The Hebrew University of Jerusalem. (2010, March 9). Friction: All may look smooth, but there are 'bumps' along the way. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2010/03/100308095501.htm
The Hebrew University of Jerusalem. "Friction: All may look smooth, but there are 'bumps' along the way." ScienceDaily. www.sciencedaily.com/releases/2010/03/100308095501.htm (accessed April 17, 2014).

Share This



More Matter & Energy News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Small Reactors Could Be Future of Nuclear Energy

Small Reactors Could Be Future of Nuclear Energy

AP (Apr. 17, 2014) After the Fukushima nuclear disaster, the industry fell under intense scrutiny. Now, small underground nuclear power plants are being considered as the possible future of the nuclear energy. (April 17) Video provided by AP
Powered by NewsLook.com
Honda's New ASIMO Robot, More Human-Like Than Ever

Honda's New ASIMO Robot, More Human-Like Than Ever

AFP (Apr. 17, 2014) It walks and runs, even up and down stairs. It can open a bottle and serve a drink, and politely tries to shake hands with a stranger. Meet the latest ASIMO, Honda's humanoid robot. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
German Researchers Crack Samsung's Fingerprint Scanner

German Researchers Crack Samsung's Fingerprint Scanner

Newsy (Apr. 16, 2014) German researchers have used a fake fingerprint made from glue to bypass the fingerprint security system on Samsung's new Galaxy S5 smartphone. Video provided by Newsy
Powered by NewsLook.com
Porsche CEO Says Supercar Is Not Dead: Cue the Spyder 918

Porsche CEO Says Supercar Is Not Dead: Cue the Spyder 918

TheStreet (Apr. 16, 2014) The Porsche Spyder 918 proves that, in an automotive world obsessed with fuel efficiency, the supercar is not dead. Porsche North America CEO Detlev von Platen attributes the brand's consistent sales growth -- 21% in 2013 -- with an investment in new technology and expanded performance dynamics. The hybrid Spyder 918 has 887 horsepower and 944 lb-ft of torque, but it can run 18 miles on just an electric charge. The $845,000 vehicle is not a consumer-targeted vehicle but a brand statement. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins