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Civil engineering

Acoustics Metamaterials for Engineering Noise Control

Metamaterials possess useful properties not found in naturally-occurring or other manmade materials. In metamaterials, the effective density and elastic moduli can attain negative values. When one of these quantities is negative, the medium does not support any propagating waves in a range of frequencies and there is a “stop band". This provides an opportunity of using them as nearly perfect compact noise screens. Few of the potential metamaterial noise control applications have been investigated so far. The proposed research will respond to the engineering challenge of finding lightweight materials for sound and vibration reduction particularly at low frequencies. The project will contribute particularly to the reduction of noise and vibration at frequencies below 250Hz since such low frequencies are attenuated less by walls and other structures in common constructions and can cause severe disturbance. As well as having many civilian applications, this is of military interest as metamaterials could be used as effective blast reflectors.