The effect of trim mounts selection on noise transmission through typical aircraft fuselage-trim structures

摘要

The cross-section of a typical commercial or business aircraft consists of light, flexible interior panels mounted to the fuselage primary structure with a thermal/acoustic insulation package filling the gap. Proper selection of isolator mounts for the interior panel is critical to minimize the structure-borne noise path into the passenger cabin. An investigation was conducted to compare the effect of isolator mount properties on the noise transmission through a typical aircraft fuselage cross-section. Four mounting configurations were studied – two mounts with different stiffness characteristics, rigid mounts and no mounts (fully decoupled system) – using a representative fuselage structure, insulation package and trim panel. Air- and structure-borne insertion loss measurements were conducted for each configuration. Significant differences were observed with respect to the rigid mount configuration. Statistical Energy Analysis (SEA) models were compared to each of the tested configurations. Good correlation between the SEA models and measured insertion loss deltas were achieved if the coupling loss factor representing the fuselage-mount-trim junction included the impedance calculated from the measured blocked transfer accelerance for the isolator.