Will Work With Bell To Analyze New Materials

Vanderbilt University is spearheading a study of rotorcraft reliability. The five-year, $1.5-million project was commissioned by the FAA, which says it's responding to the unusual increase in the number of chopper accidents.

From the mid-1990s to 2004, the number of medevac crashes in the US nearly doubled. The NTSB pinned most of the blame for those crashes on weather, terrain, and pilot error.

But the FAA says rescue flying is challenging enough without adding in equipment failures.

"The margin for error in flying a helicopter, especially in rescue missions, is very slim," says project principal investigator Sankaran Mahadevan. "We want to make sure that helicopter pilots don’t have to deal with equipment failure, such as metal fatigue, on top of the challenges of shifting winds, unseen obstacles like power lines, birds flying into the blades, and space limitations of maneuvering in tight spots."

The new study will analyze fatigue issues giving special attention to the newer light-weight materials in fashion with manufacturers.

"Lighter materials can translate into fuel economies," Mahadevan said, "But the industry needs more data on how these new materials will perform over time. We are going to help develop that knowledge base to guide rotorcraft design as well as maintenance schedules."

In conjunction with Bell Helicopter in Fort Worth, TX, engineers from Vanderbilt will conduct controlled lab tests on materials. They'll use results to build computer models that can then simulate material fatigue.

"In addition to needing information about the materials, we need better understanding of how the entire structure of a helicopter functions under a variety of performance requirements," Mahadevan said. "Helicopters have complex structural geometry and are subject to a variety of loading conditions, even without taking into considerations the unknowns involved with the new materials."

The FAA hopes the study will help guide manufacturers and users in developing more effective inspection and maintenance programs.

FMI: www.vanderbilt.edu