Gear Noise, Vibration, and Diagnostic Studies at NASA Lewis Research Center

Abstract : The NASA Lewis Research Center and the U.S. Army Aviation Systems Command are involved in a joint research program to advance the technology of rotorcraft transmissions. This program consists of analytical as well as experimental efforts to achieve the overall goals of reducing weight, noise, and vibration, while increasing life and reliability. This paper highlights recent analytical activities in the areas of gear noise, vibration, and diagnostics performed in-house and through NASA and U.S. Army sponsored grants and contracts. These activities include studies of gear tooth profiles to reduce transmission error and vibration as well as gear housing and rotordynamic modeling to reduce structural vibration transmission and noise radiation, and basic research into current gear failure diagnostic methodologies. Results of these activities are presented along with an overview of near term research plans in the gear noise, vibration, and diagnostics area. Keyword: Helicopters, Gear noise, Vibration, Diagnostics, Defect analysis, Functional analysis, Weight reduction, Noise reduction, Gear teeth, Profiles, Dynamics, Models, Radiation, Failure mechanics, Methodology, Air Force Research, Lubrication, Materials, Kinematics, Transmission gears, Numerical analysis, Mathematical models, Transmisivity, Acoustics misalignment, Input output models, Deflection, Geometry, Surface, Error, Transmission , Gears. (emk)