OREGON STATE UNIVERSITY

New materials use being handicapped by outdated failure prediction methods

07/16/2009

CORVALLIS, Ore. – The optimal use of new, strong, lightweight materials that resist cracking is being held back by inadequate methods to accurately predict fatigue failures, researchers say in a new report in the journal Science.

“Some impressive advances have been made with advanced ceramics, intermetallics, and composites that are lighter weight and/or can function at higher temperatures than traditional metal alloys without failing,” said Jamie Kruzic, an associate professor of mechanical engineering at Oregon State University. “But there’s a risk the technology will stagnate unless we develop better methods that provide accurate ways to predict and prevent fatigue failures, which are those that occur after some amount of repetitive loading.”

Most products and structures, Kruzic said, are ultimately engineered with the idea of ultimate failure – literally, how far, how hard and how many times can you push a piece of material until it breaks. In systems where safety is of critical importance, such as aircraft, significant time and money is invested to make sure unexpected failures do not occur.

Fatigue failure prevention concepts that worked adequately for the base materials of yesterday – steel, aluminum, and titanium alloys – are not well suited to the new generation of materials, researchers say. Whether the ultimate applications are in aircraft engines, more efficient automobiles or replacement materials for human bones and teeth, more modern methods are needed to fully exploit the capabilities of recently developed materials, an analysis concludes.

Some promising advances have been made to address this problem, at OSU and elsewhere, by developing new prediction methods and employing both direct and indirect testing to accurately assess the material properties, Kruzic said, but more work is needed. Research at OSU has been supported by a $400,000, five-year grant from the National Science Foundation.

Meeting such challenges will allow optimization of recent designs and the implementation of even higher performance materials in future designs, researchers said in the Science article.