Air Force Research Earns UDRI’s Top Honor

Debris that gets sucked into today’s high performance military and civilian aircraft engines during take-off and other routine operations often causes small, even microscopic, damage to the leading edge of engine fan blades. But that small damage, from sand or ice, for example, can lead to rapid failure of the part and often loss of the engine.

John J. Ruschau, senior research engineer in the Materials Engineering division of UDRI, will receive UDRI’s top research award for his four-year investigation into foreign-object damage and its consequences on the fatigue life of engine fan and compression blades. The Wohlleben/Hochwalt outstanding professional research award will be presented at UDRI’s awards banquet on April 14.

The outstanding technician award will be presented to Donald Woleslagle, electro-mechanical test technician, who worked with Ruschau on the foreign-object damage project.

“It gives me a great sense of accomplishment and satisfaction, knowing that our research efforts may in some small way effect changes in future engine designs, leading to more damage-tolerant and reliable propulsion systems,” Ruschau said.

Failure of engine components accounts for nearly $500 million each year in Air Force maintenance and replacement costs, and a majority of Air Force engine-related mishaps since 1982 can be blamed on such high-cycle fatigue failures.

Ruschau’s research, performed under contract to the Air Force in the systems support division of the Air Force Research Laboratory, resulted in a leading edge sample design that serves as an affordable and reliable alternative to testing real fan blades – a process that costs hundreds rather than thousands of dollars.

It resulted in changes to Department of Defense engine structural integrity guidelines. It also provides the framework for an industry-wide test standard to address foreign-object damage and those technologies aimed at improving the fatigue resistance of engine blades.

“John has advanced the fundamental understanding of the influence of foreign-object damage on the fatigue life of gas turbine engine blades,” said Mickey McCabe, director of UDRI. “The increased knowledge has led to recognition of limitations in modern turbine engine blade design and has provided designers better tools for developing more damage-tolerant engines. That leads to a potentially significant reduction in maintenance costs, not to mention safety of the aircraft and crew. John’s research makes it possible to understand the fatigue performance of rotating engine components damaged by foreign objects with a simpler, less expensive evaluation and to minimize catastrophic failures in both military and civilian aircraft engines.”

Ruschau conceived the objectives and purpose of the investigation, designed the test methodologies to examine the debit in fatigue life and performance of a titanium airfoil design subjected to real and laboratory-induced foreign-object damage, and demonstrated the analysis schemes to explain fatigue behavior. He has presented the results at national and international forums and published in a number of peer-reviewed journals.

By Pam Huber

Campus Report, April 4, 2003