Active structural acoustic control on facades: Fid-Bau Portal

Active structural acoustic control on facades

Doll, Torsten / Kurtze, Lothar / Langen, Christian / Bein, Thilo

Nowadays noise exposure is considered one of the main environmental pollutions. Hence, a significant number of research projects are promoted throughout the European Union and worldwide that treat with the attenuation of ambient noise in daily life. Supported by the German ministry of Education and Research the object of the research project 'Active Facades for Reduction of Sound Immissions in Buildings' is the investigation of the possibilities of reducing structure borne sound and radiated noise using active techniques. In modern architecture, facades serve as the outer skin of buildings and have to fulfill the demand of static strength. However, if facades are planned in a suitable way, they can also act as a barrier of incident sound fields. Active techniques on the basis of multifunctional materials can overcome the problems of increasing weight and volume, which the passive noise attenuation methods possess. In the present work a facade specimen consists of double-glazed windows and panels, implemented in a stiff frame. With Active Structural Acoustic Control (ASAC), the active system consists of distributed sensors and piezoceramic actuators attached to the laminar elements of the facade. By inducing anti-vibrations the structural vibrations caused by the surrounding airborne noise are minimized, thus reducing the radiated noise efficiently. Furthermore, with piezoceramic stack actuators integrated into the frame, an adaptive interface is designed preventing structure borne sound from being transmitted. With that configuration active damping and uncoupling effects can be investigated. The performance of both setups strongly depends on an effective control system. Therefore different control concepts including adaptive algorithms and model based control are designed and tested in the numerical environment. The reduction of the noise radiation achieved by the active System is estimated by BEM (Boundary Element Methods) calculations. Utilizing a DSP (Digital Signal Processing)-System the results can directly be validated at the demonstrator facade at Darmstadt University of Technology.