Guided Wave Focusing Imaging Detection of Pipelines by Piezoelectric Sensor Array

The sensor array-based guided wave focusing detection method can effectively improve the detection sensitivity of defects and realize the visual imaging. In this research, the three-dimensional finite element simulation model of stainless steel pipeline for guided wave focusing detection was established, and the L(0, 2) mode of guided wave was excited by applying a load on the end surface of the pipeline. And in the experiment, the excitation and reception of L(0, 2) mode guided waves on the outer surface of the stainless steel pipeline were realized by the piezoelectric transducer array. A 16-channel guided wave focusing experimental system was integrated to conduct the defect detection experiments on a stainless steel pipe with diameter of 140 mm and wall thickness of 5 mm. The total matrix data acquisition was performed, and then the amplitude total focusing (TFM) imaging and sign coherence factor (SCF) imaging of the pipe were realized. In this way, the experimental results showed that the pipeline defect detection method and the system proposed in this research can achieve the longitudinal and circumferential positioning and imaging of defects, like holes and scratches.