Non-Destructive Evaluation of Plastic Pipeline Cracks

The presence of defects in polyethylene (PE) pipes for natural gas transport can lead to catastrophic failures given the flammable nature of the accident. Third party damage to the external surface of pipeline is among the most common reasons for pipeline failure. In addition, the presence of manufacturing defects on the internal surface of pipeline can result to internal crack growth during pipeline operation. This paper attempts to expand the scope of guided-wave Ultrasonic Testing (UT) to detect both external and internal cracks in a PE pipe, because in its current state, UT is mostly restricted to long range inspection in steel pipes. A laboratory setup is assembled for wave-based monitoring of pipes in controlled damage conditions. The preliminary results demonstrated the potential of UT for detection of both types of cracks, and the findings are used to develop a numerical model which can be later be used to investigate a wide variety of pipeline defects. The outcome of this study establishes the potential of UT to detect both external and internal cracks in PE pipes.