Failure Analysis on Pressure Leakage of FRP

The fiberglass reinforced plastic (FRP) pipe used in the ground gathering system of an oil field occurred leakage failure during the pressure test on site after installation. Investigations were performed to identify the most probable causes of the pipe failures. Take three types of specimens for the study, which is the leak position of failure line; the non-leaked position of failure line and the standby pipeline after insulation. The study was conducted by reviewing the background of the incident, visual physical inspection, mechanical property test and finite element analysis. The reason for the failure of this batch pipe is that, a large number of circumferential cracks appear on the outer wall of the pipe under the external force dominated by the bending stress, which reduced the overall internal pressure performance and caused the leakage failure of the pipe line. The leakage failure during the pressure test on site is mostly located in the transition zone of the pipe body to joint, which is due to the discontinuity of wall thickness and uneven material.