A finite element technique is developed for three-dimensional dynamic analysis of risers and tendons. A cylindrical beam finite element is derived on the basis of a Lagrangian formulation taking into account large displacements and rotations in order to account for substantial changes in the geometry of the structure. The material is assumed to be linear elastic. The formulation takes into account the coupling between bending, axial and torsional deformations. Two hybrid finite elements are obtained from the conventional element in order to overcome the ill-conditioning of the stiffness matrix resulting from the large differences between bending, axial and torsional stiffnesses. Applications to both rigid and flexible risers are presented and the results of a parametric study on a deep-water riser are discussed.
