Elastic interaction of adjacent corrosion defects in pressurized pipelines: finite element modeling

Purpose The interaction of closely spaced corrosion defects is an important factor in pipeline integrity assessment. Elastic interaction is commonly inferred from peak stress values; however, explicit guidance on its magnitude and spatial extent under practical operating conditions remains limited. This study therefore aims to quantify the magnitude, spatial extent, and governing parameters of elastic interaction between adjacent corrosion defects under service-level loading using a systematic finite element framework. Design/methodology/approach This study presents a systematic finite element investigation of the elastic interaction between closely spaced cylindrical corrosion defects in pressurized steel pipelines. The interaction effects were quantified as functions of the normalized defect depth, normalized defect diameter and normalized edge-to-edge spacing. The elastic interaction was evaluated using the von Mises stress extracted from the circumferential stress bands surrounding each defect and referenced against a single-defect baseline response. Differences between the stresses on the ligament-facing side and far side of each defect were further examined to characterize the interaction-induced asymmetry. The finite element model was verified against the classical analytical solution for an open-ended thin-walled cylinder subjected to internal pressure and mesh convergence was established for the extracted stress measures. Findings The results show that the elastic interaction is the strongest at small defect spacings, increases substantially with defect depth and decays rapidly as spacing exceeds approximately three defect diameters. Beyond this distance, both the interaction intensity and asymmetry become negligible. Originality/value This study provides a practical basis for the assessment of the elastic interaction between closely spaced corrosion defects in pressurized steel pipelines.