超材料调控倏逝导波的结构损伤超分辨率成像方法

针对既有导波成像方法成像分辨率无法突破二分之一波长这一瓶颈，本课题将开展基于超材料调控倏逝导波的板状结构损伤超分辨率成像方法研究。具体研究内容包括：研究特定损伤倏逝导波场的复杂特征，揭示多共振弹性超材料对倏逝导波所携带损伤亚波长信息的转化机制，获取超材料与损伤倏逝导波大波数匹配条件；优化设计具有异常色散特性的弹性波超材料，将损伤倏逝导波转换为含损伤亚波长信息的可传播导波；发展多损伤量化检测的DORT-MUSIC超分辨率成像算法，分离超材料形成的大波数导波中所含亚波长损伤散射信息，实现微小损伤以及损伤亚波长形貌的精细成像；构建板状结构损伤超分辨率成像检测平台开展相关实验验证研究。本课题预期将实现对金属板结构中微小裂纹损伤的成像分辨率提高一个数量级。最终形成的板结构微小损伤超分辨率成像检测新原理、新方法，将推动我国高端装备结构损伤检测/健康监测技术的发展，具有重要的科学意义和工程应用价值。

Aiming at the challenge that the imaging resolution of the existing guided wave-based imaging method cannot break through the half of wavelength, this project will conduct the research on the super-resolution imaging method in plate structures based on the controlling of evanescent guided waves (EGW) using metamaterials. Firstly, study the complex characteristics of the evanescent guide wave field induced by specific damages and reveal the regulation mechanism of EGW which includes the sub-wavelength information of damages. Thereby obtain the matching condition of wave number of EGW with that of metamaterials. Secondly, design and optimize the metamaterials to realize the specific dispersion characteristics, which can convert the EGW to propagation guided waves (PGW) that signature the sub-wavelength details of damages. Thirdly, develop a DORT-MUSIC imaging algorithm to separate the damage information of scattering waves and then realize the super-resolution imaging of sub-wavelength damages and damages with sub-wavelength morphology. Finally, set up the super-resolution imaging platform and carry out a series of designed experimental investigation. This project will form novel principles and methods of super-resolution imaging of micro-damage in plate structures, which is expected to improve the imaging resolution of one order. The research results will promote the development of structural damage detection/health monitoring technology for critical device in China, which has significant importance in science and engineering.