Guided wave inspection of long steel pipe using non-axisymmetric end loading transducer

In order to overcome the conventional guided wave transducer's unsuitability for piled pipe inspection, a non-axisymmetric end loading (NEL) transducer is designed and studied in this paper. Propagation of guided waves in a hollow cylinder and the circumferential distribution of echoes from notches are studied by using the finite element (FE) method under different end loading conditions. The simulated results show that when the radial angle between the first notch on a pipe and the NEL transducer is zero, the energy distribution from notch echoes is a maximum, even if there are different direction notches on the pipe. A specially designed clamp is developed to fix the NEL transducer to the pipe. Finally, the simulated and experimental results show that the circumferential and axial location of the notch on pipe can be located by rotating the NEL transducer during the process of inspection.