An Analysis for Effect Factors of Ultrasonic Guided Wave Tomography in Structural Health Monitoring

Localized flaws such as corrosions in petroleum pipelines often cause fragility, impairing integrity and shortening service lifetime of the structures. There has been much interest recently in monitoring the integrity of the pipe structures. Ultrasonic guided waves provide a highly efficient technique for rapid pipe inspection because they can be made to propagate significant distances in pitch-catch configurations. Crosshole tomographic geometry is formed in such pitch-catch configurations when transmits and receivers are respectively laid along two parallel circumferential belts around the pipe. Considering the pipe as an unwrapped plate, we investigate the adapation of the tomographic reconstruction in seismology to the guided wave inspection of a pipe. Various effects such as transducer arrangement, mesh precision, sampling interval and iterative algorithm on tomographic reconstruction are analyzed. The results provide a theoretical basis for quantitative detection of pipeline flaw using guided wave tomography.