Numerical Simulation of Damage to Submarine Pipe-in-Pipe Systems Impacted by Falling Objects

Subsea pipe-in-pipe systems frequently encounter challenges from impact loads caused by falling objects, resulting in dents and damages that lead to oil and gas leakage. This study conducted a comprehensive analysis using a nonlinear explicit dynamic finite-element model, considering 108 parameter scenarios, to study the damage pattern of the inner pipe. An economic benefit analysis was done for the steel consumption of the pipe. Research revealed that the impact position of falling objects and the gap between the centralizer and the outer pipe are critical factors in determining the extent of damage to the inner pipe. To mitigate inner pipe damage, optimal measures include increasing the outer pipe wall thickness, enhancing the grade of steel pipes, and maintaining the gap between the centralizer and the outer pipe 40 mm. This study contributes to a deeper understanding of the structural response of falling objects impacting subsea pipe-in-pipe systems, providing valuable insights for the design and operation of such systems.