August 23, 2007

Friction center's research among 'most cited'

by Tim Crosby

peter filip

Caption follows story

CARBONDALE, Ill. — Engineering advances are built on those that come before. Like building blocks, they reach higher and farther with each new discovery. So each advancement must be strong, straight and true and researchers must cite them when using their findings to further their own work.

Research from a laboratory at Southern Illinois University Carbondale recently provided a major cornerstone for work in the friction field, which touches virtually every aspect of engineering at one point or another.

The engineering journal Wear recently announced that an article authored by Peter Filip, director of the Center for Advanced Friction Studies at SIUC, was among the top 50 articles researchers cited from 2002 to 2005.

Wear, a nearly 2-inch-thick monthly journal dedicated to friction engineering topics, is widely recognized as the top such journal in the world. For researchers, just getting published in Wear is an honor. But having your article among the most cited is a major event for the University and the center.

"It really shows that the quality of research we do here at SIUC is quite high," Filip said.

Ian Hutchings, editor in chief of the journal, agreed in a letter to Filip.

"The popularity of your work suggests that it is of particular interest and value to researchers in the field," wrote Hutchings, a professor at the University of Cambridge and an acknowledged expert in the friction field.

The article outlined the discovery of a "friction layer" that occurs when two objects, such as a brake pad and disk, rub together. The research looked specifically at friction layer formation in polymer matrix composite materials for brake applications.

Filip explained that even though engineers may know the type of materials rubbing together and their individual characteristics, they have not been aware that the process forms another altogether different material between the two objects. This friction layer occurs everywhere — braking systems, computer hard drives, engines and machines — where friction exists, and that likely has major implications for engineering and environmental issues.

"We are creating totally new qualities as we brake," Filip said. "We proved that this friction layer exists, and it exists everywhere. That is why we are cited so often."

The research and accompanying article are based on an exhaustive six-year study involving the entire U.S. brake market. The SIUC Center for Advanced Friction Studies worked with the late Zdenek Weiss, director of the Central Analytical Laboratory in Czechoslovakia, with the U.S. National Science Foundation and the Czech Ministry of Education funding the work. SIUC researchers also conducted some work off-site at Oak Ridge and Brookhaven national laboratories.

"It involved a great deal of systematic work, with lots of experimentation, evaluation and more experiments," Filip said, adding that the center's panel of industry advisers also helped support the research.

The discovery could yield great engineering advances in braking systems, as well as countless other applications where pieces of machinery rub together.

But the environmental implications might also be of huge importance.

In the United States alone, there are about 230 million road vehicles in use at any given time, with about 16 million new ones added each year, Filip said. Manufacturers use some 3,000 different raw materials in those vehicles' various braking systems.

This large variety means friction layers emit a nearly endless variety of new substances.

"This could have major environmental implications," Filip said. "The material created in brake systems may not be as safe as the original material. We don't know what is out there, and it could be a real mess."

As a result, SIUC is now applying to the NSF to look deeper into the environmental questions. Filip proposes a team approach, working with researchers at the University as well as others. The approach, for instance, would have researchers at the University of Florida examining how plants and animals absorb the friction layer materials, and those at Technical University of Ostrava, in the Czech Republic, looking at genotoxicity.

Regardless where the research goes from here, Filip said SIUC should take great pride in the Center for Advanced Friction Studies' status in the engineering community, as reflected by the number of times its work is cited by engineers and researchers around the world.

"Our researchers do high-quality work and that is shown by this article's citations," Filip said. "It reflects well on our University."