Research On Sound Propagation Characteristics Of Tunable Periodic Structures

With the continuous development of various fields of industry and technology,many equipment and instruments are becoming more and more accurate in the process of use,and these devices may be affected by the environment and cause vibration.In the face of these problems,the research on vibration reduction is developing rapidly.But so far more vibration damping materials are used are dampers,memory alloy,these more traditional vibration damping devices.Based on the above problems,this paper proposes a research on sound propagation characteristics of adjustable periodic structure.The band structure of periodic structure has the characteristics of specific band gap,and it is applied to daily devices that need vibration reduction.The structure is simple and the material is easy to obtain,and it has the characteristics of adjustable frequency and strong adaptability.In this study,uav is used as the main test device,and a multi-channel real-time vibration measurement system is designed to carry out the vibration test experiment of UAV and the subsequent vibration reduction experiment measurement.The main work of this paper is as follows:（1）Completed this topic is based on sound propagation characteristics of adjustable periodic structure study of research work,starting from the related development of vibration isolation,at the same time,the study of sound waves in periodic structures widely research,and sums up the phononic crystal at home and abroad research status and development trend of related technologies,to lay the foundation for follow-up study.（2）This paper introduces the theory of phononic crystal band correlation,mainly introduces two kinds of calculation methods of phononic crystal band in detail,and based on this,carries on the band calculation simulation of one or two dimensional periodic structure with MATLAB.（3）The multi-channel real-time vibration measurement system was designed,and the upper computer of the system was designed by Lab VIEW.The vibration measurement experiment of uav was completed by using the system,and the main vibration frequency points of UAV were obtained,which laid a foundation for the subsequent periodic structure design and vibration reduction experiment verification.（4）The frequency response of a one-dimensional and simplified three-dimensional model of the initial periodic structure was analysed by COMSOL,and the influence of different factors on the energy band of the periodic structure was also analysed,based on which the design and fabrication of the adjustable periodic structure was carried out.In this paper,through the research on sound propagation characteristics of tunable periodic structures,in addition to exploring its sound transmission characteristics,it is also applied to daily devices and verified the effect of vibration reduction,which expands the application of periodic structure in vibration reduction technology,which has certain significance.