Abstract: In order to study the influence of flexibility of the boom on the dynamic responses of moored crane ship, governing equations for the dynamic response of a crane-ship coupled with the pendulum motion of the payload are derived on the basis of Lagrange’s equations. The boom is modeled based on finite element method, while the payload is modeled as a spherical pendulum of point mass. Numerical studies are then carried out for a real crane ship. The dynamic response is studied by using numerical method. Simulations show that the excitation frequency of the wave and deformation of the boom have important influence on the dynamic response of the crane ship. The rigid-flexible coupling model is proved more feasible to describe the dynamic characteristic of the system in comparison with rigid model. The analysis identifies the significance of key parameters and reveals how the system design can be adjusted to avoid critical conditions.

Key words: Finite element method, Lagrange’s equation, Moored crane ship, Rigid-flexible coupling, Converged flow sliding valve, Pressure distribution, Steady Axial flow force, two-phases flow