Study On The Properties Of Acoustic Grating Modified Phonon Crystal And Periodic Solid Plate

Sonic crystals(SCs) have received a large number of attentions in recent decade for its intrinsic rich dispersion relation ability to manipulate acoustic waves/elastic waves. With the development of study, acoustic device with single functions gradually not satisfied with the needs of people. In order to meet the requirements in acoustics integration, people began to study sonic crystal systems modified by periodic gratings which produce new phenomena and properties.Acoustic surface structure is another object of study related to the article,this kind of research started in realization of the structured surface wave. During the study of anomalous transmission, reflection and refraction have been confirmed, it show some other unique properties and advantages, gradually becoming a new hot spot for acoustic research.By solving the elastic wave equation and making use of finite element numerical simulation, this article focuses on some features of the periodic grating modified sonic crystal system and electromagnetic acoustic similar phenomenon of acoustic surface structure. Specifically, this paper mainly involves the following aspects:In the second chapter, based on the periodic grating modified of two dimensional sonic crystals, three kinds of situations are analyzed: the perfect sonic crystal, the symmetric composite systems, the asymmetric systems. The results show that introduced various additional acoustic gratings, the vectors will get a different increment transverse in the sonic crystal interface. By using appropriate acoustic symmetrical gratings, which can greatly improve the properties of perfect sonic crystals; By using asymmetric gratings, we have obtained a novel splitting device.In the third chapter, further study of this composite system,we get some functional designs. Introducing asymmetrical grating on both sides, the wave asymmetric transmission device was designed; We design a more efficient surface wave conversion device; On the high symmetry around the point M, we get a high quality directional beam collimator.In the fourth chapter, by use of a rigid solid surface plate carved periodic subwavelength grooves, the designer surface waves(SAW) are obtained. Further introduced a small increment grooves, their dispersion relation of a rigid solid surface plate carved periodic subwavelength grooves are below the waterline. It indicated a non-leakage features; In addition we increase the groove depth, the dispersion line deviated from waterline, which means increasingly localized and the cut-off frequency is gradually decreased. Then, introducing a linear increase of groove depth, the results show that the surface acoustic wave getting closer to a solid plate in the vertical direction and In the direction along the surface propagation distance is shorter. A class "inductor" devices was designed.