Study of a Top Tension Riser Using a 4-Node Shell Element Based on Vector Form Intrinsic Finite Element Method

The top tension riser plays a pivotal role in deep sea oil and gas extraction, operating within a complex environment influenced by flows, waves, and the top buoyancy module. Accurately simulating its dynamic response in such intricate marine conditions is paramount. Current research predominantly involves modeling full-scale, large aspect ratio top tension riser using beam elements. In contrast, shell elements offer distinct advantages, presenting a superior representation of the pipeline’s shape and more precise reflection of the flexural and torsional stress distribution in top tension riser. However, employing shell elements for top tension riser studies introduces several challenges. Notably, the requisite number of shell elements is considerably higher than that of beam elements for the same model. In traditional finite element nonlinear structural dynamics computations, an increased element count exponentially intensifies computational difficulty. Consequently, modeling and computing the dynamic response of large aspect ratio top tension riser with shell elements pose formidable research challenges. To address these issues, we develop a four-node shell element based on the vector form intrinsic finite element method, utilizing parallel computing to enhance computational efficiency for top tension riser. This study applies the developed method to compute the dynamic response of top tension riser, employing parallel computing for efficient calculations. The dynamic response under the influence of uniform flow and top buoyancy module motion is investigated. The program is further utilized for the analysis of pipeline stress in top tension riser, validating the precision of the computational method. This research presented innovative methods for the study of the tension risers.