Corotational Beam Element for Nonlinear Dynamic Analysis of Offshore Production Lines

Resumo

To ensure the safety and functionality of floating platforms, nonlinear dynamic analysis of mooring lines, production risers, offloading hoses, and control/service umbilicals is essential. DOOLINES, an object-oriented computational framework, performs these analyses in the time domain using the Finite Element Method (FEM). Originally, DOOLINES employed spatial truss elements with six translational degrees of freedom, which directly represented axial stiffness but only indirectly accounted for bending stiffness. This work extends the capabilities of DOOLINES through the implementation of a corotational beam element (12 degrees of freedom: 6 translations and 6 rotations), which explicitly models axial, bending, and torsional stiffness. The adopted corotational formulation enables the capture of large displacements and rotations while maintaining the assumption of small strains. Comparative simulation results with truss elements and a reference commercial software show excellent agreement, thus validating the proposed implementation. Although the new element requires greater computational resources, its comprehensive formulation proves particularly advantageous in scenarios where bending and torsional effects are significant, such as in offshore production risers