钢-混凝土结构弱粘接界面缺陷的超声导波检测

Ultrasonic guided wave detection of weak bond interface defects in steel-concrete structures

钢-混凝土结构是土木工程中的一种常用结构形式,钢与混凝土粘接处可能出现弱粘接甚至完全脱粘的缺陷,严重影响结构的安全性。该文提出利用空气耦合超声导波衰减的方法实现钢-混凝土结构粘接状态的非接触无损检测方法,分析不同厚度粘接界面对超声导波衰减的影响。基于全局矩阵技术对钢-混凝土结构求解理论频散方程和衰减曲线,得到界面层不同粘接条件下的理论参数及衰减特性。建立不同粘接条件的有限元模型,定量分析不同模态对粘接缺陷的检测敏感度。研究界面层厚度分别为1 mm和2 mm两种情况下S0能量的衰减情况。研究结果表明:S0模态可有效判断粘接结构的粘接状态,对于同一界面层厚度,随着界面粘接条件变弱,S0最大幅值与A0最大幅值比不断增大;不同厚度同一粘接条件下,2 mm相较于1 mm该值更大。该方法在钢-混凝土结构粘接界面缺陷的检测方面具有良好的应用价值和发展前景。

Steel-concrete structure is a common structural form in civil engineering.It may have weak or even complete debonding defects in the bond between steel and concrete so that seriously affect the safety of the structure.In this paper,a non-contact non-destructive testing method for the bonding state of steelconcrete composite structures by air-coupled ultrasonic guided wave attenuation is proposed,and the influence of ultrasonic bonding on the attenuation of ultrasonic guided waves is analyzed.Based on the global matrix technique,the theoretical dispersion equation and attenuation curve are solved for the steel-concrete layered structure,and the theoretical parameters and attenuation characteristics of the interface layer under different bonding conditions are obtained.The finite element model with different bonding conditions was established to quantitatively analyze the sensitivity of different modes to the detection of bonding defects.The attenuation of S0 energy in the case of interface layer thickness of 1 mm and 2 mm was analyzed separately.The results show that the S0 mode can effectively judge the bonding state of the bonded structure.For the thickness of the same interface layer,as the interface bonding condition becomes weaker,the ratio of the maximum amplitude of S0 to the maximum amplitude of A0 increases continuously.Under bonding conditions,the value of 2 mm is larger than that of 1 mm.The method has good application value and development prospect in the detection of weak bond interface defects in steel-concrete structures.