声波/弹性波超材料功能结构的阻抗匹配和梯度优化

This project is aimed to solve the difficult problems of acoustic impedance mismatch and constraints in manufacture for acoustic/elastic metamaterials, by means of the establishment of the theory of impedance-tunable coordinate transformation. With the help of this new theory, it will be easier to manufacture functional structures and devices of acoustic/elastic metamaterial with high performance, and will promote the progress of their engineer production. Under the new theoretical framework, continuous impedance functions will be set up in the virtual space, which will directly intervene the whole process of “determining the path of wave propagation, characterizing of macroscopic parameters of continuous medium, and designing the microstructure of metamaterials”. Therefore, the boundary impedances will be matched flexibility by the settings of these impedance functions, as well as the internal structure of the transformation medium will be optimized by an arbitrary gradient impedance function. With the advantages of this new theory, the determination of the microstructure scale will be more accurate, and the complexity of manufacture will be reduced much more. On the basis of the our researches in the past and in the present, designs and manufactures of metamaterial devices with 4 different kinds of microstructures will be finished to verify the high performance in broadband, high energy transmission, and so on. Finally, this new theory will become terminator of current barriers, and supply systemic theoretical basis, analysis means and implementation methods, and will support the realization of intelligent component with arbitrary controling of acoustic/elastic wave.

课题以建立阻抗可调的坐标变换理论为基础，突破阻抗失匹和制备瓶颈为目的，佐以制备实现高性能器件，以期推进声波/弹性波超材料功能结构实用化、工程化进展。新的理论框架在虚拟空间设置连续的阻抗函数，直接贯穿“波控介质功能实现/宏观连续化表征/微结构设计”全过程，可实现更为系统和灵活地调控边界阻抗匹配设置、优化变换介质内部任意阻抗梯度结构、精确确定亚波尺度微结构设计参数、降低制备复杂度。并结合课题组已有工作积累和正在开展的研究内容，提出了含有4类微结构及其器件设计制备的研究方案，以兹验证。本项研究最终将突破当前壁垒，为声波/弹性波调控器件的逆向设计提供系统的理论依据、分析手段和实现方法，也为下一步实现任意调控声波/弹性波的智能构件奠定基础。

本课题的研究目标是建立阻抗可调的坐标变换理论为声波/弹性波超材料功能结构设计和制备提供更有效途径。本项研究以连续介质力学为基础，在虚拟空间设置连续的阻抗函数，建立了宏观波动行为与材料等效密度和等效模量之间的数学关系，实现了边界阻抗的自动匹配；在此基础上，进一步建立了可靠的阻抗变化的梯度模型，针对边缘非线性梯度区域渐变，采用拓扑结构等设计，获得了功能结构层次和材料层次设计的最优化方案。最终，利用阻抗可调的坐标变换方法，突破器件工程化制备的瓶颈，形成了主被动的波控器件逆向设计和优化制备方法。在国内外期刊发表论文二十余篇（SCI 收录23篇，EI 收录3篇），参加国际和国内学术会议报告十余人次，其中全国大会特邀报告两次。创新成果还展开应用推广，申请国家发明专利7项（已授权4项，已公开3项）。相关工作形成的专利技术和文章，受邀写入英国皇家化学学会新书《Materials for Advanced Manufacturing and Applications》第6章“Advanced Manufacturing of flexible piezoelectric arrays”。.本项研究提出的波动调控新机理克服了传统声学材料的物理瓶颈，逐步实现了基于宽带超薄手性超表面的完美吸/隔声声学覆盖层，服务于国家十四五重大计划高机动水下航行器型号项目、军委科技委创新研究项目、高性能声学传感器研制项目等重要装备中的减振降噪需求，为军民装备应用的隐蔽性和探测性提供可靠保障。