• Nykänen, Hannu
• Aalto, Samu
• Lindroos, Tomi
• Kosonen, Pasi
• Tanttari, Jukka
• Uosukainen, Seppo
• Nousiainen, Esa
• Kataja, Jari
• Saarinen, Ari
• Mellin, Velipekka
• Antila, Marko

Abstract

During the last decade fundamental research on smartstructures using intelligent materials has raisedindustrial interest. One of the most challengingapplication field is noise and vibration control. Thestrongly coupled phenomena vibration and noise limit thedesign of highly advanced and efficient lightweightstructures. To face the challenge European Union hasgranted funding for the Integrated Project IntelligentMaterials for Active Noise Reduction - InMAR as the keyEuropean Union funded project in the area of IntelligentMaterials within the FP 6.VTT's main focuses in InMAR project are in- developing novel concepts for vibroacoustic propertiesof light weight composite materials- developing new large surface structural and acousticsensor-actuator pairs for sound transmission controldeveloping new local feedback control methods, especiallyfor multi-channel active sound transmission loss control- implementing active sound profiling for car interiorsound quality control- applying the developed materials, actuators and controlmethods in passive design, and in active systems in carsound package design and elevator wall sound transmissionloss increase.The first realization of novel composite panel concept atVTT is a GFRP panel with striped core made of twodifferent materials. The panel shows up to 10 dB bettersound insulation compared to the reference (homogenousstiff core) panel. Two types of polymer material basedactuator-sensor elements have been developed togetherwith Panphonics Oy, one for active structural control andthe other for active acoustic control of soundtransmission loss of panel type structures. Developmentof multi-channel digitally adjustable analog controlsystem is carried out for the active systems e.g.utilising large surface polymer actuators. The developedFPAA prototype controller contains an FPAA unit board anda microcontroller. The prototype controller system hasbeen tested in active car sound package mock-up withlarge surface polymer actuator-sensor pair with up to 9dB improvement in the target frequency band withbroadband acoustic excitation. Local feedback controlsystem gives possibilities to tune and increase the soundinsulation of the sound package at selected frequenciesgiving flexibility for the sound insulation design of carsound packages and other panel like structures.

Topics

• impedance spectroscopy
• surface
• polymer
• composite