Study on evaluation method of failure pressure for corrosion cluster defects based on failure location

Abstract The interaction between adjacent defects significantly influences the internal pressure bearing capacity of corroded pipelines. Therefore, the interaction between adjacent defects must be considered as evaluating the failurepressure of pipeline with corrosion cluster defects. The existing failure pressure evaluation methods of pipeline with corrosion cluster defects have the disadvantages of complex evaluation steps and poor applicability. In the paper, the failure mode of pipeline with corrosion cluster of two or more defects is studied by burst experiment of full-scale pipeline. The results show that for the corrosion clustercomposed of defects with obvious difference in internal pressure bearing capacity, the failure position is the defect with the minimum internal pressure bearing capacity; for the corrosion cluster composed of defects with no noticeable difference in internal pressure bearing capacity, the failure location is the defect in the center of the range of corrosion cluster. Based on the failure position of corrosion cluster, a "center failure location" method is proposed to evaluate the failure pressure of corrosion cluster defects. The method takes the defect in the failure position as the center, the influence of adjacent defects which interact with the central defect on its failure pressure is considered, and then the failure pressure of pipeline with corrosion cluster defects centered on the failure location is evaluated. Compared with the existing evaluation methods, the prediction error of this method is not reduced, but the evaluation conditions are less and the evaluation method is simple to operate and more applicable.