Aircraft Engine Response Due to Fan Unbalance 690613
The paper discusses the analytical procedures required in computing the engine support system dynamic loads induced by a fan unbalance. The detailed analyses involve the coupling of pylon and engine vibration modes in the modal coordinate system and the determination of the steady state response due to an unbalance in the rotating fan. Gyroscopic effects, engine case ovalization flexibility, and a redundant restraint to an external support are investigated. Graphs are presented that summarize the computed results and show the sensitivity to gyroscopic effects.