人工周期结构中的弹性波调控及应用基础研究

Elastic wave propagation in artificial periodic structures(APSs), such as phononic crystals and acoustic metamaterials, has received much attention recently. The behavior of wave motion in APSs is commonly studied by using the theory of wave band structures, by which one can examine the mechanisms of wave manipulation, explore some new wave phenomena, as well as various application possibilities, such as control of vibration and noise, and design of acoustic devices. Recently, aimed at the control of sound and vibration, we have made great efforts to explore wave manipulations by APSs, including the reflection, absorption, and guiding of elastic waves. We discovered the phenomena of strong wave directivity in flexural lattice structures, low frequency absorption in locally resonant structures, the existence of super-wide gap formed by the coupling between resonance and Bragg gaps, and gap broadening effect induced by negative Poisson materials. These findings show that there is further need to explore the mechanisms and behavior of wave propagation in APSs, which are of great interest in the area of vibration and noise control. This project is proposed to explore systematically the wave manipulation mechanisms of APSs, to address physical understanding of the novel wave phenomena that were found by us recently, and to study the associated paramedic influences on the wave behavior. We hope the outputs of this project can provide some new ideas for the control of vibration and noise, and advance somewhat the theory of APSs, especially the mechanisms of wave motion in APSs, which can be useful and helpful for more possible engineering applications.

对弹性波传播特性的研究是振动与噪声控制研究的核心基础问题之一。声子晶体、声学超材料等人工周期结构的研究通过能带理论考察弹性波入射人工周期结构的传输行为，实现对弹性波调控机理的深入分析，发现新的物理效应，并为振动与噪声控制技术及声学器件的研究提供新的技术途径。以声振控制为背景，项目组近期在研究人工周期结构对弹性波反射、吸收及引导的调控中，发现了弯曲波的定向传播、局域共振低频吸声、布拉格带隙与局域共振带隙耦合的带宽拓展及基于负泊松比设计的带宽拓展等新效应，表明围绕振动与噪声控制，人工周期结构的弹性波调控机理还需要深入探讨。本项目将在此基础上，系统研究人工周期结构的弹性波调控机理，深入揭示上述物理效应的产生机制、影响因素及变化规律，探索其在振动与噪声控制中应用的新方法、新途径。本项目的研究将拓展和深化对人工周期结构弹性波调控机理的研究，同时也将为工程周期结构的振动与噪声控制提供新的思路。

声子晶体、声学超材料等人工周期结构的研究通过能带理论考察弹性波入射人工周期结构的传输行为，实现对弹性波调控机理的深入分析，发现新的物理效应，为振动与噪声控制技术及声学器件的研究提供新的技术途径。以声振控制为背景，项目系统研究人工周期结构的弹性波调控机理，深入揭示上述物理效应的产生机制、影响因素及变化规律，探索其在振动与噪声控制中应用的新方法、新途径。项目主要研究成果:.(1)探讨了局域共振人工周期结构的共振单元参数对结构布拉格与局域共振两种带隙的调控规律，发现了两种带隙的相互耦合效应，揭示了两种带隙的调控机理和带隙耦合展宽的物理机制。.(2) 研究了负泊松比人工周期格栅结构的带隙特性。揭示了其带隙形成的机理，研究了提高周期格栅结构中弹性波的衰减性能的优化设计。 研究了薄膜型人工周期结构的隔声特性。深入探讨了薄膜型人工周期结构的隔声机理，深入分析了隔声性能的影响因素及影响规律。.(3)深入研究了压电分流型人工周期结构薄板的带隙特性和带隙形成机理，以及电路参数对带隙内传播常数的影响；揭示了关键的带隙影响因素和影响规律，探索了压电分流阵列在卫星微振动抑制中应用的可行性。. (4) 研究了局域共振人工周期结构在不同背衬条件下的吸声机理及影响因素，揭示了其共振吸声机理、多频谐振吸声机理及空腔间多重散射的影响规律。研究了水声吸声人工周期结构在线激励下的声辐射模型，提出了隔声去耦性能的影响因素及优化思路。.(5)研究了声学变换介质的坐标变换设计，提出了用较少分层结构实现较好隐身效果的设计思路，分析了优化设计的机理。得到了控制五模材料参数实现各向异性并在一定范围内调节的设计方法。研究了实现了弯曲波“斗篷”、弯曲波波导等器件的弯曲波坐标变换设计。.项目全面完成了申请书规定的各项研究内容。在该项目资助下，共发表论文14篇，其中SCI收录14篇。项目研究成果可为工程周期结构的振动与噪声控制提供一条新的技术途径，具有广阔的应用前景。