Objectives and content
It is the aim of the project to study and validate the use of active foils as acoustic and/or structural actuator in active noise control applications (ANC) and active structural acoustic control (ASAC).
An active foil consists of one or more thin layers of 'active' material that expands or contracts in one or more directions when exposed to electrical voltage. In this way bending or compression waves can be induced into the active foils. Depending upon the boundary conditions and upon the type of the induced wave the active foil can be used as an acoustic or structural actuator (loudspeaker or vibration exciter). in both cases the action of the foil is distributed over its surface and not limited to a local point as is the case for classical vibration actuators or loudspeakers.
The use of active foils as acoustic actuator in ANC applications has not been reported before in literature but offers, compared to classic loudspeakers, several advantages which will be explored in this project. In general it is expected that the active foils will be more efficient than classic actuators due to their size, their flexibility and their distributed character. Several new approaches will be explored among them the integration of an active foil in a passive absorbing layer, whereby the complimentary characteristics of passive and active acoustic control are optimally combined. Also the use of these foils in the development of a volume velocity acoustic sensor will be examined. The study will contain the following major activities:
- development of integrated actuator/sensor configurations, - numerical simulations to optimise the actuator/sensor configuration, - development of control methods,
- experimental parametric study on laboratory set-ups,
- validation on prototype.
Following applications will be explored in detail in the proposed project:
- Use of active foils to improve the transmission loss through double panel partitions.
- Use of an integrated passive/active layer to increase the insertion loss of single panels.
- Use of active foils to reduce structure borne sound of vibrating panels.
These configurations will be tested and validated on simplified laboratory set-ups. The most efficient control strategy will be implemented and validated for a practical application (sound encapsulation, and car interior).
Funding SchemeCSC - Cost-sharing contracts
161 11 Bromma
06903 Sohpia Antipolis