Vibroacoustic analysis of an innovative windowless cabin with metamaterial trim panels in regional turboprops

The purpose of this work is to study the possible noise reduction, in terms of sound pressure level, in the passenger cabin of a regional turboprop aircraft under multiple tonal and broadband noise components characterizing the noise generated by the engines during cruise flight conditions. In particular, we want to show the acoustic performances of innovative passive noise and vibration technologies, such as acoustic metamaterials applied to the trim panel of the cabin, in the low-frequency range, from 100 to 300 Hz. Moreover, the removal of windows from the passenger cabin is evaluated, in acoustic terms. Analyses are performed using a numerical tool, Actran, a finite element based software, and a numerical model of a regional aircraft fuselage. According to the results, metamaterials seem to have significant acoustic performances that lead to a reduction in noise and therefore an increase in passenger comfort.