A Time-Reversal Defect-Identifying Method for Guided Wave Inspection in Pipes

Abstract

The temporal-spatial focusing effect of the time-reversal method on the guided wave inspection in pipes was investigated theoretically in the current research with a transfer function. The amplitude of the time-reversed wave propagating along the pipes was not only determined by the characteristics of the defect and the location for observation but also by the location of the time-reversal transducers. Especially, the quantity of transducers distributed around the pipe in the circumferential direction was found to be important in applying such time-reversal method. The results demonstrate that the time-reversal method can be used to enhance the inspection energy for the guided wave inspection in pipes and to locate the defects in the circumferential directions. Once the time-reversed signals obtained from the guided wave inspection are applied on a numerical model, the defects can be recognized by the motion of the time-reversed wave transmitting along the pipe model. Numerical simulation and experimental results are provided in this paper to illustrate the validity of such defect-identifying method.