Parametric approach to primary structure modelling of aircrafts for cabin noise analysis in FEM

The goals of the European Green Deal require the development of low-emission aircraft propulsion systems that take sustainable fuels into account. However, there is a conflict of objectives between effective fuel reduction and noise development of the propulsion system, as particularly efficient propulsion concepts are often based on open rotors which usually cause increased exterior and interior noise. In this context, the creation of precise vibroacoustic models is becoming increasingly important in order to ensure a valid evaluation and optimization of aircraft interior acoustics in the early phases of the design process. The primary structure of the entire aircraft is an important component of the transfer path between external excitation and the resulting cabin noise, because it is decisive for the spatial propagation of structure-borne noise. This publication therefore focuses on the parametric creation of complete primary structure models for aircrafts based on preliminary design data with a level of detail that is relevant for the vibroacoustic frequency range. Generally valid modeling approaches for finite element models, e.g. the correct choice of mesh resolution, that were derived from experiments are also shown in detail. In combination with the external excitation, qualitative statements on the vibroacoustic properties of the aircraft can already be made at primary structure level, by calculating spatially and spectrally integrated energy distributions. This is demonstrated for two different aircraft configurations using validated operating excitations of V2500 engines in cruise flight.