Stress analysis of damaged submarine pipeline using finite element method

The objective of this paper is to assess the stress level and consequent serviceability in the vicinity of a dry buckle caused by unknown accidental loads. A case study of a severely dented submarine pipeline, whose dent profile is known apriori, is presented in this paper. A finite element model has been generated with shell elements. Elasto-plastic analysis was carried out to simulate the probable magnitude of the equivalent static load due to the impact and corresponding stress level of the pipeline. The portion of the pipeline subjected to high locked-in stress is ascertained. Analysis has been performed with two different grades of the most commonly used material, viz. API 5L X-52 and X-60, to investigate the effect of SMYS (Specified Minimum Yield Stress) on the stress level and on the magnitude of equivalent static load.