J-tube Pull-In of Rigid Risers.

Sammanfattning: This work covers an advanced finite element analysis (FEA) approach of investigating riser pull-in through an existing J-tube up to an offshore platform. A riser is a vertically oriented piping used to deliver fluid, gas or other relevant packages upward. The challenges of this process consists of several bending segments along the J-tube, multiple contact issues in conjunction with pull-in of the riser, the modeling of the large geometry of the arrangement as well as the complex friction mechanics. The main focus of this project is on incorporating above mentioned details in the software programs ANSYS and SIMLA. The numerical model includes a rigid riser, J-tube with fixed supports, seabed, pull-in wire and vessel back-tension; in order to compare the suitability for pull-in analyses of the two programs. This work includes evaluation of important design criteria such as maximum pull-in force, plastic strain and stresses along the riser, analytical calculations as well as comparing the outcome between all of the obtained results. The results can be used to verify the capability of the pull-in winch for a platform.