Application of statistical energy analysis to the design of crew rest compartments

Abstract

Longer flight times for modern commercial aircraft have led to the need for crew rest compartments. Noise levels in the crew rest compartments must be conducive to proper rest and recuperation. Statistical Energy Analysis (SEA) has been used to develop a 777 crew rest compartment design that achieves appropriate noise levels at acceptable weight and cost. In this paper the design of a 777 overhead crew rest compartment is outlined using SEA design tools and methods. Noise data were gathered in flight to distinguish airplane source components and develop model inputs. Crew rest panels, the airplane fuselage, and acoustic volumes were modeled as SEA subsystems by taking into account geometry, material properties, modulus, and damping. A model was built, excited with inputs, and analyzed to determine energy flow paths and acoustic pressure at receiver locations. Prospective add-on treatments were then assessed to engineer an effective noise control package. The model development was supplemented by laboratory sound transmission loss testing of individual components. The good agreement between the laboratory tests and individual SEA models of the components increased confidence in the approach. Once the crew rest was installed on the airplane, the measured in-flight noise levels closely matched the SEA estimates.