Experimental Analysis of the ACASIAS Active Lining Panel

Abstract

The participants of the EU-project ACASIAS develop advanced concepts for aerostructures with multifunctional capabilities. Within work package 3 an active system for noise reduction is integrated into a curved lining panel. The objective is the reduction of the interior sound pressure level by increasing the transmission loss of the lining panel. The application scope includes current propeller driven aircraft and future aircraft with counter-rotating open rotor (CROR) engines. The drawback of these CO2-efficient engines is their high sound emission in the frequency band up to 500 Hz. Active noise reduction systems are able to achieve performance in this frequency band while passive sound insulation materials fall behind. Thus, active systems are the key technology to avoid unacceptably high noise levels for passengers. During the last period of the project the main experiments are conducted. The active lining with its dimensions of 1300 × 1690 mm^2 (W × H) is mounted in a setup in the acoustic transmission loss test facility of the DLR. Several tests in different categories are run to characterize the vibration and sound transmission behavior of the lining. In this paper the active lining and its components are briefly introduced and the results of the modal and the thermal testing are presented.