NASA - National Aeronautics and Space Administration

Glenn-Led Technology Ensures Safety and Savings

One of the most challenging component design and certification requirements for commercial jet engines is to try and prevent a "blade-out" rotor failure event, which can result in catastrophic loss of aircraft and/or passengers. Engine blade-out occurs when a sudden change in speed causes a fluctuation in rotor spin resulting in a blade overstress condition, or when a blade, or group of blades, fatigues from repeated cyclic stresses.

Image right: Damaged engine case from blade-out testing. Credit: NASA

Testing rotor dynamics and blade-out conditions to ensure safe operation is extremely expensive, time consuming and labor intensive. An award-winning "tool kit" of simulation software developed by a Glenn-led team of industry, government and university researchers has the potential of saving aircraft engine companies as much as 10 percent in design and development costs per year. Companies may use the team-generated software to replace costly testing procedures with analytical simulations of the aircraft rotor dynamics system, as well as predict a situation where a transient blade-out might occur.

"Glenn provided technical expertise, project leadership and facilitated funding that enabled the long-term research and exchange of resources necessary to create a comprehensive simulation of a rotor dynamics system to enhance aerospace industry designs," explained team lead Dr. Charles Lawrence, Structures and Materials Division. "Our Engine-Air Frame Structural Simulation Team collaborated for more than four years to fully comprehend the structural needs and develop the rotor dynamics to develop new analysis models, computational algorithms and simulation software tools that would better predict the structural response of the complex engine-airframe rotor dynamics system."

The team's efforts culminated in technology demonstration, transfer and commercialization through sustained investment from NASA's Aviation Safety and Security Program, Space Act Agreements, grants and other partnerships. Prediction of engine blade-out improved by 50 percent, with a design cycle time reduction of 25 percent. The improved simulation tools also enable engine designers to consider a wider selection of design configurations.

Key partners of this technology include Boeing, GE Aircraft Engines, Pratt & Whitney, Rolls Royce, Honeywell, Livermore Software Technology Corp., the Ohio Aerospace Institute, The Ohio State University, the Federal Aviation Administration and MSC.Software. MSC.Software implemented the system software in the 2004 release of its finite element analysis (FEA) code, MSC.Nastran.

"In addition to aeropropulsion applications, the new code will better ensure the structural integrity and safety of rotating equipment used in microgravity experiments aboard the space shuttle and station and the KC-135 as it goes through simulated maneuvers," Lawrence noted. "The code was also employed in the design of Boeing's 787 Dreamliner, which is scheduled to enter service in 2008. The design of this plane incorporates the advanced features of the enhanced code along with the most advanced materials and technologies available to airlines around the world."

With the support of NASA's Aviation Safety and Security Program, Glenn scientists and engineers continue to work with industry partners and academia to develop and apply advanced, affordable technologies to make air travel safer.

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S. Jenise Veris
NASA's Glenn Research Center