An investigation on the collapse response of subsea pipelines with interacting corrosion defects

• Published in: Engineering structures 2024-12, Vol.321, p.118911, Article 118911
• Main Authors: D’Aguiar, Savanna Cristina Medeiros, Motta, Renato de Siqueira, Afonso, Silvana Maria Bastos
• Format: Article
• Language: English
• Subjects: Collapse response; Corrosion; Failure analysis; Interaction rules; Ovalization; Temperature
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2024.118911

Subsea pipelines are usually affected by corrosion. Corrosion defects can occur anywhere along the pipeline and may interact with each other. The interaction between corrosion defects is pivotal in determining the response of subsea pipes subjected to external pressure. This work uses nonlinear Finite Element (FE) analyses to evaluate the collapse of subsea pipelines containing multiple corrosion defects. The computer system called PIPEFLAW is used to automatically generate and analyze corroded pipeline models. The FE-based solutions are validated against experimental results in the literature and achieved good agreement. Then, extensive parametric analyses are conducted to assess whether an interaction exists between adjacent longitudinal and circumferential defects with different geometries. The results from parametric study suggest that defect arrangements play a fundamental role in the interaction rules. The longitudinal critical spacing at which defects can be considered isolated was found to be 50 times the pipeline thickness, and the circumferential defects should always be considered interacting. Additionally, based on the FE simulation data, this study introduces expressions for adjustment factors for predicting the collapse pressure, considering the effect of the initial ovality (factor fo) and temperature variation (factor ft). The proposed adjustment factors are valuable tool for predicting the collapse pressure of pipelines. So, these findings expand our understanding of corroded subsea pipeline collapses and offer practical insights for the industry. •The collapse response of pipes with multiple corrosion defects is studied.•FE models are validated, and the interaction between adjacent defects is evaluated.•The critical longitudinal spacing from defects is established.•New adjustment factors for predicting the collapse pressure are proposed.•The findings enhance the understanding of subsea pipeline corroded collapse and provide practical insights for the industry.