Pipeline thickness estimation using the dispersion of higher order SH guided waves

Abstract

Abstract Thickness measurement plays an important role in monitoring pipeline corrosion damage. However, the requirement of knowing shear wave velocity in the pipeline material for popular ultrasonic thickness measurement limits its widespread application. This paper proposes a method utilizing cylindrical shear horizontal (SH) guided waves to estimate pipeline thickness without prior knowledge of shear wave velocity. The inversion formulas are derived from the dispersion of higher order modes with the high-frequency approximation. The waveform of the example problems is simulated using the real axis integral method. The data points on the dispersion curves are processed in the frequency domain using the wave number method. These extracted data are then substituted into the derived formulas. The results verify that employing higher order SH guided waves for evaluating thickness and shear wave velocity yields less than 1% error. This method can be applied to both metallic and non-metallic pipelines, thus opening new possibilities for health monitoring of pipeline structures.