A comparative study on failure pressure between cracked and corroded pipes: Investigation of load sharing between steel and composite patch

This research aims to present a comparative study on the failure behavior of the corroded and cracked pipelines under internal pressure, considering both strength and deformation aspects. The research mainly emphasizes the importance of understanding the structure’s deformation and the size of area experiencing plastic strain before failure, highlighting its crucial role in transferring load from base metal to repairing material in rehabilitated systems. To this end, the experimental burst test on the corroded and cracked pressurized cylinder are conducted to compare their fracture response, maintaining the same ratio of the affected thickness. Additionally, numerical modeling of the unrepaired and repaired (using CFRP) corroded, externally and internally cracked pipes are comprehensively investigated. While the bearing pressure of the unrepaired corroded and cracked pipes are in the same range (3.54% difference in burst pressure), the findings reveal significantly different deformation behavior between the two cases. It is illustrated that the size of plastic deformation in the defected area governs the load transfer between base metal and CFRP in repaired systems, resulting in 150% difference in burst pressure of the repaired cracked and corroded cylinder.