Mohammad Vaghefi

Subsea hydrocarbon pipelines are subject to thermal expansion and are susceptible to axial forces, which can lead to buckling unless these effects are appropriately controlled. This analysis investigates the impact of the number and initial spacing of imperfections on lateral and upheaval buckling of subsea pipes. Finite element models were established in ABAQUS and subsequently validated by analytical solutions in order to determine their accuracy. 24 pipeline conf igurations with differing numbers (2, 3, and 4) and spacing values (100–600 m) of imperfections were simulated. The results indicate that increasing the number of imperfections raises the critical buckling temperature and reduces the buckling amplitude for both lateral and upheaval cases. Conversely, increasing the spacing between imperfections leads to a decrease in critical temperature and an increase in the buckling amplitude. Furthermore, lateral buckling occurs at lower critical axial loads and temperatures than upheaval buckling. These findings underscore the critical importance of the strategic placement in effectively controlling buckling behavior and ultimately enhancing the stability and integrity of subsea pipelines under thermal loading.