10th International Conference on Offshore Mechanics and Arctic Engineering, 23-28 June 1991, Stavanger, Norway.
The paper presents results of a combined experimental and analytical study on the dynamic responses of a deepwater tripod tower platform to regular and random waves. The purpose of the study was to understand and to predict the near resonant responses of a large diameter deepwater structure. The experimental effort involved the fabrication of a large hydroelastic model at a scale of 1:50 and the testing of it in a 200x12x7m deepwater wave tank. The fundamental natural frequencies were identified by modal testing of the structure in water. They were found to be in close agreement with the finite element model results. The structural responses were predicted using a finite element model. Relative velocity formulation was used in Morison's approach to wave solved in the time domain. Realistic hydrodynamic coefficients, obtained from the model experiments, were used in the analysis. A separate force measuring experiment was conducted using a prominent portion of the cylinder. Good agreement between the experimental and the predicted results was obtained.