Prediction of the collapse pressure for thick-walled pipes under external pressure

• Finite element analyses of the collapse behavior for thick-walled steel pipes were performed.
• The classic Timoshenko's equation can generate large error for thick-walled pipes.
• The effects of main affecting factors on the collapse pressure were investigated.
• 441 finite element models of thick-walled pipes with practical configurations were constructed and analyzed using Python.
• A simplified equation for predicting the critical plastic collapse pressure was given.

Collapse behavior of offshore pipelines under external pressure is a primary concern for ultimate limit state design criteria of structural integrity. In this work, finite element analyses of the collapse behavior for long, moderately thick-walled steel pipes under external hydrostatic pressure were performed. The effects of initial ovality, yield stress and yield anisotropy on the collapse pressure were investigated. Besides, 441 finite element models of thick-walled pipes with practical configurations were constructed and analyzed using Python (the programming language within the finite element software package ABAQUS). A simplified equation for predicting the critical plastic collapse pressure was given and recommended for calculating the pressure capacity of thick-walled pipes. The accuracy of the simplified equation was verified by the experimental results from other researchers.