Abstract: A simple and effective method is proposed to apply the hydrodynamically induced mass to the marine wind power structure in the finite element analysis. The proposed method can be readily implemented into the ABAQUS software, by which the preprocessing efficiency is improved in the finite element analysis. A finite element model is developed, and the influences of the hydrodynamically induced mass and different boundary conditions on the natural vibration of marine wind power structure are analyzed. Based on the finite element method, the sensitivity analysis is carried out for the hydrodynamically induced mass and various boundary conditions, through simulating the response of offshore wind power tower under the earthquake loading. The numerical simulation and theoretical analysis show that the proposed method yields good results. Applying the hydrodynamically induced mass decreases the natural frequency of the structure, and as the order number increases, the natural frequency and its absolute magnitude increase. The boundary conditions can influence the modal parameters more significantly than the hydrodynamically induced mass, and the natural frequencies of each order decrease significantly if the viscoelastic transmitting boundary condition is adopted. The model with a viscoelastic transmitting boundary yields a greater displacement response compared to the model with a fixed boundary.

Key words: hydrodynamically induced mass, ground-bucket foundation-tower system, viscoelastic transmitting boundary, modal analysis, seismic loads, displacement response