Abstract:

Ultrasonic guided wave time-reversal focus method is a common technique to detect small pipeline defects. But pre-judgment of the defect approximate location is needed to determine starting point and width of time-reversal window, which in practical is commonly difficult to achieve. For solving this problem, a section time reversal inspection method with pipeline guided wave is proposed. The tested pipeline is firstly divided into multi-interval. Then the received inspection signal of each section is time reversed and re-excited in proper order. So time-reversal inspection signals for different sections are achieved. The simulation and experimental results show that when the signal-to-noise ratio of time-reversal inspection signal for some section is better than conventional guided wave detection, it can be determined that there is one defect in the inspected section and the specific location of defect can be also accurately calculated. Conversely, it can be determined that there is not any defect in the inspected section. This method can be effectively used for small defects inspection of the entire inspected pipeline.

Key words: pipeline inspection, section, time reversal, ultrasonic guided waves