TY - RPRT
T1 - Final assessment of vibro-acoustic source strength descriptors
of helicopter gearboxes
AU - Ohlrich, Mogens
AU - Rasmussen, Ulrik Møller
PY - 1996
Y1 - 1996
N2 - Two novel measurement techniques have been developed for
quantifying the vibro-aqcoustic source strength of lightweight
helicopter gearboxes. The accuracy, robustness and implementation
of these methods have been examined by a comprehensive
investigation, including theoretical studies of simple multi-modal
beam systems and extensive experiments with more realistic small
scale models and with large, detailed 3/4-scale test structures of
a medium-size helicopter. In addition, partial verification tests
have been conducted with the Eurocopter BK 117 helicopter and its
main rotor gearbox. The results of this work are essential as
input for any prediction code of the internal noise in a
helicopter cabin, because the prediction requires knowledge of the
major sources, that is, the rotors, engines and gearboxes.
AB - Two novel measurement techniques have been developed for
quantifying the vibro-aqcoustic source strength of lightweight
helicopter gearboxes. The accuracy, robustness and implementation
of these methods have been examined by a comprehensive
investigation, including theoretical studies of simple multi-modal
beam systems and extensive experiments with more realistic small
scale models and with large, detailed 3/4-scale test structures of
a medium-size helicopter. In addition, partial verification tests
have been conducted with the Eurocopter BK 117 helicopter and its
main rotor gearbox. The results of this work are essential as
input for any prediction code of the internal noise in a
helicopter cabin, because the prediction requires knowledge of the
major sources, that is, the rotors, engines and gearboxes.
M3 - Report
BT - Final assessment of vibro-acoustic source strength descriptors
of helicopter gearboxes
ER -