Sound Transmission Through Triple Panel Partitions

Abstract

Sound radiation from vibrating panels plays a crucial role in the study of interior noise in transportation vehicles. In recent years, several patents have been issued for inventions in the field of sound reduction technologies to mitigate aircraft noise. This work presents a theoretical analysis and simulations to investigate sound transmission through plate-like multi wall structures. An analytical model is developed to predict sound transmission through infinite-sized triple panel partitions placed in a rigid baffle, from a viewpoint of practical noise control. A numerical procedure is also developed to evaluate the transmission characteristics of finite partitions due to an incident diffuse field. The method is based on a hybrid FEM/Rayleigh methodology and utilizes numerically calculated sound transmission loss of flat multi panel partitions and box like cavities with idealized boundary conditions. Two simplifying assumptions are made: the surrounding medium is air and the radiated sound power is calculated by an array of discrete elemental radiators. Several examples are presented to demonstrate the accuracy of the proposed approach. A theoretical performance analysis is finally carried out on a triple panel partition representative of a more complex triple wall aircraft-type window. The testbed design, used for this study, is guided by an effort to quantify sound insulation capabilities of aircraft windows with a specific focus on passenger's protection against noise transmitted through fuselage panels.