Currently, vibro-acoustic metamaterials are a topic being researched across the globe in the area of noise and vibration reduction. They can be used to reduce the amplitudes of harmful structure vibra-tions and noise to such a low level and across such a wide range that would not be possible using conventional measures. They are applied to passive or active local resonators usually arranged periodically on the component to be influenced. The local resonators are tuned into the natural fre-quency in question and are placed on the basic structure at distances smaller than half the wavelength of the frequency to be influenced. “Stop bands”, which are areas where no wave propagation is possible, occur in this frequency range during the transfer function.
During the “MetaVib” project, Fraunhofer researchers managed to achieve an effective structure-borne noise reduction of up to 20 dB in defined frequency ranges. This knowledge is provided in a toolbox that facilitates the task of designing and optimizing structures as vibro-acoustic metamaterials at different levels of detail. The design process varies according to the application and supports efficient proto-type development in industrial follow-up projects.
On the body-in-white of a vehicle door, a reduction in vibrations and radiated noise of up to 20 dB in defined frequency ranges was achieved in the laboratory.
Area of Expertise: Lightweight Design