A Numerical Study on Responses of Submerged Floating structures Undergoing Vortex-induced Vibration and Seismic Excitation

The dynamic responses of submerged floating structures undergoing vortex-induced vibration and seismic excitation were numerically investigated. The tube and tethers of submerged floating structures were assumed as an Euler-Bernoulli beam and the hinged supports of the tube, respectively. The wakes behind the tube were regarded as distributed oscillators. With the consideration of the fluid-structure interaction, the prediction model of the responses was established. Numerical results show that the tube responses of the submerged floating structures subjected to the vortex induced forces and seismic excitation have the feature of nonlinearity. Superposition method is not suitable for the solution of such responses. As the tether spacing reduces, the maximum displacement of the tube, the constraint forces and the constraint moments of all the supports of the tube reduce. In the same variation interval of the tether spacing, the maximum displacements reduce most its values. The tube vibration of the submerged floating structure presents more periodicity when the tether spacing reduces.