Jet engine vibration model for estimating pylon–wing interface loads for realistic structural excitation

Abstract The noise passengers experience in aircraft cabins originates from different sources. One of them is structure-borne noise originating from jet engines. In the case of wing-mounted engines, minor imbalances of rotating engine components can result in a vibration of the wing structure. The wing vibrations are transmitted to the fuselage, potentially giving rise to substantial structure-borne noise. While there are state-of-the-art methods for calculating the acoustic emissions of jet engines during relevant flight conditions, i.e., take-off, cruise and landing, this is not the case for operational vibrations of jet engines. This publication focuses on the development of an engine vibration model on the basis of limited data in the early design phase. The result of the vibration model is a vibration load profile that can be used to excite numerical aircraft models. In combination with the respective jet and fan noise excitation profiles acting on the fuselage, this model will enable future studies to perform holistic assessments of the noise acting inside the cabin. The developed model combines a theoretical approach for the estimation of unbalance forces with measurement data from in-flight experiments with a research aircraft. An exemplary vibration load set for a V2500 engine is calculated and applied to a full aircraft model to show the fuselage response.