Quantitative characterization of axial defects in pipes based on circumferential SH0 waves
JIA Jiuhong;LIU Tianyang;LIU Xuecheng;LIAO Zuoyu;ZHANG Xiancheng;Key Laboratory of Pressure Systems and Safety, Ministry of Education, East China University of Science and Technology;
As the service life of the pipeline increases, the damage accumulates, eventually leading to a leak or explosion. The introduction of guided waves in monitor pipeline damage online is an important guarantee to ensure its safe operation. The fundamental circumferential shear horizontal(CSH0) wave has excellent characteristics, such as difficult to disperse and sensitive to axial defects of the pipeline. It is very suitable for quantitative characterization of axial defects of pipelines. Based on the propagation characteristics of the CSH0 guided wave in the pipeline, the quantitative relationship between the CSH0 guided wave and the axial defect of the pipeline is studied by finite element simulation and experiment. The results show that the higher the radius of curvature of the pipeline, the closer the propagation characteristics of the CSH0 mode are to the propagation characteristics of the SH0 mode in the plate. The reflection coefficient and transmission coefficient of the guided wave signal show a monotonous change to the length and depth of the axial defect. Based on this, a corresponding nephogram for the quantitative characterization of defects is established, which can be used to evaluate the defect size.