振幅突变超表面的弹性导波调控机理

The development of lightweight, practical and stable methods on the manipulation of elastic guided waves attract keen interests and are meanwhile considered as a difficulty. Metasurfaces provides a new avenue to achieving this goal due to its small size, easy preparation, and wide working frequency. However, it is limited to control elastic waves merely by phase change. This project aims to theoretically and experimentally investigate new elastic metasurfaces for the precise control of guided waves in elastic plates. Based on the existing phase modulation approach, we will first develop a new theoretical model of metasurfaces by taking the amplitude change into account. Considering multiple modes of guided elastic waves in plates, the modal transformation of elastic metasurfaces will be studied to precisely control reflected and transmitted waves of different modes. Then, a variety of novel elastic metasurfaces, such as the directional waveguide metasurface and the modal transition metasurface, will be proposed, fabricated and experimentally studied. The project will provide the theoretical basis and technical support on the next generation of elastic metasurfaces, and will promote its development and application in the field of elastodynamics.

发展轻便实用且稳定性高的弹性导波调控方法是弹性动力学领域的研究热点和难点。超表面技术因其体积小、易于制备、工作频率宽等优势为实现该目标提供了新的思路，但目前受限于仅通过相位突变来调节弹性波场。本项目拟开展新型的弹性超表面理论和实验研究，以提高其对弹性板中导波的精准调控能力。首先建立相位和幅值同时突变的弹性超表面波场调控的理论模型；针对弹性板中导波多种模态耦合的特性，揭示弹性超表面的模态转换机理，实现对各种模态反射波和透射波的精确控制；设计并制备弹性导波定向传播和模态转换等多种新型弹性超表面结构，并进行实验验证。最终，本项目将从理论和实验上为新一代弹性超表面的设计和应用提供理论基础和技术支持，推动其在弹性动力学相关领域的发展和应用。

本项目开展了振幅突变超表面的弹性导波调控机理的理论和实验研究，按计划完成了任务书设定的研究内容。基于双各向异性、非局部效应、高阶衍射效应以及修正的惠更斯-菲涅耳原理等，建立了幅值突变弹性超表面的波场调控理论；提出了正向设计和逆向优化相结合的弹性超表面设计方法，设计、验证了高效波束控制、非对称传输、任意路径能量输运、承载隔振一体化以及地震波隔离等功能的新型弹性超表面，提高了其对弹性导波的精准调控能力。在项目资助下，发表SCI论文8篇，申请发明专利2项；培养博士研究生3名、硕士研究生5名；参加国际会议3人次、国内会议11人次，并作口头报告8人次。