(1. National Key Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China) (2. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China)
Acoustic metamaterials are one of the current research hotspots in acoustics and materials science. Acoustic metamaterials are generally defined as a kind of composite materials, which are designed by artificial structures on characteristic physical scales and exhibit acoustic properties that exceed conventional materials. Due to the excellent subwavelength acoustic performance and the possible applications in some extreme condition, the acoustic metamaterials have attracted much attention. In recent years, a large number of laboratory-grade acoustic metamaterials have been reported with the continuous maturity of additive manufacturing technology. However, due to high production costs and complex preparation processes, the application of acoustic metamaterials is still facing severe challenges. In this paper, the current research status of several kinds of acoustic metamaterials is introduced in detail, the technical and technological problems in applications for them are discussed in detail, and the latest research progress of testing and research methods for acoustic metamaterials is briefly introduced. Finally, the future prospect and development directions of acoustic metamaterials was forecasted from the perspective of practicality.