Abstract
The paper presents an overall design approach for smart light-weight structures equipped with thin piezoelectric wafers as actuators and sensors to actively control the noise radiation. The design approach is based on a finite element model, which includes the passive structure, the piezoelectric wafers, the surrounding fluid and the controller as well. The proposed overall modeling approach is briefly presented and applied to design an active diesel engine to reduce the noise radiation. The simulation results are compared with measurements performed on a laboratory set-up. It is shown that the experimental and numerical results are in good agreement and a substantial noise reduction of the smart engine is achieved. Then the quality of the designed smart engine is also tested under real operating condition (four-cylinder common rail diesel engine) on an acoustic engine test bench, where engine run-ups (900 to 3000 rpm) are made and evaluated. Even under these conditions the noise level of the smart engine is reduced by approximately 4 dB, which indicates the noise reduction potential of the designed system.
