Theoretical study on upheaval buckling of subsea pipelines with temperature-dependent thermal properties at different carbon contents

Subsea pipelines composed primarily of carbon steel are susceptible to upheaval buckling in the presence of elevated temperatures and pressures. The thermal performance of submarine pipelines is a crucial factor that controls the buckling behaviour, and the carbon content of carbon steel pipelines significantly influences their thermal properties. This paper establishes a theoretical model for subsea pipeline upheaval buckling that takes carbon content and temperature into account, and a comparison with the classic solutions is used to validate the parsing solutions. The influence of temperature-dependent thermal properties under different carbon contents on the buckling configuration and post-buckling behaviour of submarine carbon steel pipelines is analysed. The findings indicate that, when taking into account how carbon content affects material qualities, the temperature dependence significantly affects the upheaval buckling of carbon steel pipelines. Furthermore, at the same temperature, subsea pipelines with higher carbon content have a lower coefficient of thermal expansion and thus experience less thermal-induced axial compression. Subsea pipelines' critical buckling temperature rises in a linear fashion as the amount of carbon in the pipeline increases. For higher carbon content, both the maximum stress and the buckling displacement amplitude decrease in the post-buckling stage.