混凝土损伤识别中的时间逆转成像方法

时间逆转成像技术具有定位准确和操作简单之特点，本文将其运用于混凝土结构损伤的检测．通过提取各换能器单元的发射信号和损伤散射信号构建超声波传播的传递矩阵然后对其进行奇异值分解，获得包含损伤信息的奇异向量；采用多重信号分类(multiple signal classification, MUSIC)算法，分别基于数值模拟数据和实验实测数据对混凝土结构内部损伤进行成像，实现了准确的损伤定位，并将成像结果与偏移成像法进行对比．此工作探索了将时间逆转成像技术应用于混凝土结构内部损伤实际工程检测可行性，为无损检测技术人员定性或定量分析混凝土结构的内部缺陷提供理论参考．

Application of Time Reversal Imaging Method on Concrete Structural Damage Identification

The time reversal imaging technology has the merits of accurate positioning and simple operation, in this paper it had been applied to the detection of damage of concrete structures. The transfer matrix of ultrasonic transmission was constructed by extracting transmitted signals from transducer arrays and scattered signals from damages, and then it underwent singular value decomposition and the singular vectors containing information about the damage were obtained. The damages of concrete structure were imaged by MUSIC (multiple signal classification) algorithm based on the data from simulations and experiments respectively, a precise positioning of damage was obtained, and a comparison with the result from migration imaging was made. This work explored the feasibility of employing the time reversal imaging technology to detect the internal damage of concrete structures in real situation. It also provided a theoretical reference for nondestructive testing engineers to analyze the internal defects of concrete structures qualitatively or quantitatively.