Testing, simulation, and design for analyzing the behavior of lined pipes under torsion

Offshore oil and gas development requires increased corrosion resistance due to exposure to harsh and corrosive environments. The use of lined pipes with both significant mechanical and corrosion-resistant properties has become increasingly widespread in the offshore oil and gas industry. The potential pipeline torsion trend during the installation stage may affect the structural integrity of the adopted lined pipe and has become threats to offshore construction. This study conducted torsion tests on lined pipes and captured the structural behaviors. Finite element (FE) models were developed to investigate the failure modes, the developments of the liner wrinkle and the interaction stress between the outer and liner pipes. The mechanism of how the interaction behaviors developed and the improvement of composite action between the constitutive parts had been quantitively discussed. Additionally, a series of parametric studies were conducted to study the effects of the outer pipe strength, the outer pipe thickness and the length of the lined pipe. Finally, the improved method for the design torque, considering the contribution from the liner pipe, has been proposed. This study can provide valuable references for the design and installation of lined pipes under torsion.