MODELING AND DESIGN OF A SMART DOUBLE-PANEL SYSTEM FOR THE CONTROL OF SOUND TRANSMISSION INTO AIRCRAFT CABIN

Nowadays, the level of interior cabin noise in modern aircraft has been reduced significantly compared with noise levels in the past because the double-panel design of aircraft sidewall systems has been much optimized. Furthermore, new composite materials are now used in the design of trim panels and additional sound absorption materials are also used in fuselage structures. However, this improvement in interior noise reductions is limited to mid-range and high-range frequencies (above about 1000 Hz). In fact, double-panel sidewall systems currently used in aircraft designs are ineffective at reducing low-frequency sound transmission (below about 1000 Hz). Furthermore, this problem is more likely to become much worse in the future because of the rapid progress in the manufacturing of aircraft with powerful jet engines and high speeds, which lead to increases in the exterior sound level and turbulent boundary layer vibrations. During flight, the exterior fuselage skin panel of an aircraft is subjected to incident acoustic waves with a broad range of frequencies. When the incident acoustic waves transmit through the airborne and structure-borne sound paths of the aircraft double-panel structure, sound energies with mid-range and high-range frequencies are largely absorbed by the passive noise control components, while low frequency sound waves transmit into the cabin trim panel without any attenuation. These acoustic waves vibrate the trim panel, causing sound power radiation from the panel into the aircraft cabin. The control of low frequency sound radiated power can be achieved by actively attenuating the structural vibrations of the trim panel using an effective active structural acoustic control (ASAC) method. This research presents the development and application of an effective methodology of an active structural acoustic control system for the reduction of low frequency sound transmission through an aircraft double-panel sidewall structure. The implementation of multi-input-multi-output (MIMO) controllers is used for the active control system, which electrically activates a set of novel high-performance piezoelectric actuator elements and velocity error sensors. The actuator elements are installed in the cavity between the fuselage skin panel and cabin trim panel, and arranged so as to generate out-of-plane control point forces acting on the trim panel. A set of velocity sensors is bonded on the inner surface of the trim panel to measure its structural velocities and predict its sound power radiation.

Department dc:contributor.department

Mechanical and Industrial Engineering

Year dc:date.issued

2018

Author dc:creator

• Aloufi, Badr

Advisor dc:contributor.advisor

• Behdinan, Kamran

• active structural acoustic methods
• control system
• piezoelectric actuator
• Smart Structures and Materials

Handle dc:identifier.uri

http://hdl.handle.net/1807/89885

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/89885