A detailed review study on acoustic Meta-materials: acoustic cloak

Meta-materials designed purposefully to reduce broad band noise which is not attainable by natural materials. Basically these are artificial materials. These materials definition is not specific. These exhibit properties which are not available in constituent materials. Properties are derived from physical structure not from their chemistry. Sometimes these are perceived as composites purposefully designed to reduce noise. Existing techniques are filtering, dampening using resonators, muffling can only control certain range of frequencies of broad band i.e. 20Hz-20 KHz but where as in case of Meta materials these can control any range of frequency because of their peculiar property. Performance of existing techniques is low also. Design and development of meta materials is the current work which focus on making different physical structures of specific material and testing for noise level reduction. Iterating on different structures of same material is the concept of Meta material. These materials have now overturned in all views of conventional aspects of sound propagation and manipulation. Performance of cavity acoustics used for broad band noise reduction is to be improved and innovation is required to do such work. Meta materials can be the replacement for the need. These materials can considerably reduce noise with same weight of material which is used in existing technique. Design of Meta material include repeating regular physical structure pattern for the whole component. When sound waves pass through specific structural pattern different frequencies are absorbed which is covering whole range. Where as in case of regular techniques only specific frequency is absorbed. In case of development of Meta material different manufacturing techniques are adopted such as moulding, proto typing etc.