Perforation analysis and limit prediction of submarine pipelines subjected to extreme impact loadings

Abstract

Submarine pipelines without embedding and coating are prone to rupture and perforation failure under heavy transverse impact loadings in the offshore petrochemical industry. In this paper, qualitative analyses of various failure modes were performed to understand failure phenomena and features. Moreover, perforation processes under transverse impact loading were investigated to understand evolution mechanisms. Furthermore, extensive parametric studies were conducted to examine the effects of various dominant and characteristic parameters, especially internal pressure, eccentric distance, and deflection angle, on dimensionless deflection and impact limits. Fitting formulas between the impact limits and various parameters were established. Finally, a modified cavity expansion model for pressurised pipelines subjected to cubic penetrator was established to predict the perforation limit and residual velocity. The results revealed the failure patterns, evolution mechanism, and impact limits under various parameters, which could be used as a guideline to supplement specifications and propose safeguards for the impact protection of submarine pipelines.