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研究圆管上的超声导波的裂纹几何尺寸与回波反射特征间的映射关系.首先,建立5组周向角度与径向深度的裂纹管道的有限元仿真模型,用脉冲-回波的方法模拟L(0,2)模态波对管道横向裂纹进行检测,提取其裂纹反射系数特征值;其次,搭建导波检测系统,加工3组周向裂纹的圆管试样,分别用单探头与4个探头进行裂纹检测试验.分析表明:试验与仿真分析得到缺陷尺寸对反射系数的影响趋势吻合;能够检测到1m以外的裂纹,轴向定位误差小于10%;裂纹回波的反射系数随着损伤程度的增大而增大.本研究为基于导波对管道横向裂纹的定位与识别提供了参考.
The relationship between the crack geometry of the guided wave on the circular tube and the echo reflection characteristics is studied.Firstly, five sets of finite element simulation models of the cracked pipe with circumferential angle and radial depth are established, and the pulse-echo method The L (0,2) mode wave was simulated to detect the transverse crack in the pipeline and the eigenvalue of the crack reflection coefficient was extracted. Secondly, the guided wave detection system was set up to process three sets of circular tube specimens with circumferential cracks. Four probes were tested for cracks.The analysis shows that the influence of the defect size on the reflection coefficient is in good agreement with the experimental results and the simulation analysis. It can detect the cracks beyond 1m and the axial positioning error is less than 10%. The reflection coefficient of crack echo The degree of damage increases and increases.This study provides a reference for the positioning and identification of transverse cracks on the pipeline based on guided waves.