On the calculation and control of structural intensities to reduce Sound Transmission through thin walled structures

Abstract

In lightweight and stiff structures like aircraft fuselages, the structure-born noise is often the dominating part in noise transmission. To efficiently use methods like active vibration reduction in order to attenuate this unwanted sound, suitable sensor information must be provided. In recent research, a new focus has been established on so-called structural intensities, a vector information on the transmitted sound energy per unit area as control target to efficiently block sound transmission within the structure. This paper discusses methods to calculate and control structure intensities for panel like thin structures. For control purposes there is a need to at least estimate these quantities from real-time sensor data. In order to better understand the behavior of the structure with respect to sound transmission, offline calculations based on enhanced measurements e.g. from a laser scanning vibrometer are also discussed. In addition, the resulting power flow information can be used to adapt sensor and actuator positions.