۲D vs ۳D Finite Element Analysis of Free Span Response in Subsea Pipelines

Free-span formation in subsea pipelines, often caused by seabed irregularities, local scour, or differential settlements, poses a significant threat to pipeline integrity through the induction of vortex-induced vibrations (VIV), fatigue damage, and potential structural failure. While two-dimensional (۲D) numerical models are widely used in early-stage designs due to their simplicity and computational efficiency, their ability to accurately predict the complex dynamic behavior of pipelines remains limited. In contrast, three-dimensional (۳D) models provide a more realistic representation of seabed geometry, pipe-soil interaction, and hydrodynamic loading, albeit at the expense of greater computational resources. This study presents a comparative numerical analysis of subsea pipelines with free spans under both ۲D and ۳D finite element models using ABAQUS software. Key parameters, including deformed shapes, natural frequencies, and simulation run-times, are extracted and evaluated. The results offer valuable insight into the accuracy and applicability of simplified ۲D models for preliminary design purposes, providing engineers with a practical framework for selecting appropriate modeling strategies based on project constraints and performance requirements. The study also lays the groundwork for aligning simplified numerical analyses with international design standards.

کلیدواژه ها:

Subsea pipelines ، Free span ، ۲D vs ۳D modeling ، Finite element method