中文摘要：

传统的无损检测方法难以识别出混凝土结构表面较深的裂缝,提出一种基于时间反转理论的表面波混凝土结构裂缝检测方法,采用有限元方法对压电激励与接收表面波的时间反转过程进行了数值仿真。根据表面波时间反转原理,计算得到重构信号,通过激励信号和重构信号的相关系数构造了损伤指数。仿真结果表明,混凝土表面裂缝越深,与表面波波长越接近,重构波形与激励波形差异越大,其损伤指数越高,说明表面波时间反转过程能够有效地识别出混凝土结构的表面裂缝。

英文摘要：

Existing non -destructive test methods are usually ineffective in detection of surface breaking cracks with large depths. It in- troduced a method suitable for detection of deep cracks based on surface wave time reversal theory. A numerical simulation based on the finite element model is performed to investigate surface cracks.A damage index was defined based on the correlation coefficient between the actuated and the reconstructed wave signals.The results of numerical simulation demonstrate that the presence of crack had a signifi- cant influence on the propagation characteristics of surface waves along the concrete.Damage of different sizes was introduced and then was correlated with the damage index. Enlarging the crack depth resulted in an increase in the level of distortion in the reconstructed wave signals, and a higher damage index was obtained.The results show the effectiveness of the surface wave time -reversal process in identifying cracks in concrete structures.