MCS Evaluations on Dynamic Responses of an Offshore Structure with Uncertainties

摘要

For an offshore structure subjected to severe wave forces, it is very important to make the dynamic response characteristics clearly for the reliable design of the structures. The random vibration approach gives very effective methods on the dynamic response evaluations for the offshore structure subjected to the forces. The characteristics of the structure and external forces have generally uncertainties on the response evaluations. It is very important for the reliability assessment to evaluate the uncertain parameter effects on the maximum response quantities. The Monte Carlo simulation (MCS) comes to an effective method on the evaluations of these uncertainties. The MCS approach in nonlinear situation is applied to evaluate the uncertainty effects on the offshore structure in the present study. The dynamic response properties of the offshore platform subjected to severe wave forces are examined by the MCS. The governing equation of motion is formulated with the finite element method for an idealized 3-dimensional offshore structure. Considering uncertain parameters in the strength of materials of the structure and the dynamic wave forces, it is very essential to clarify these uncertain parameters contributions on the responses with respect to the reliability evaluations of the offshore structure. It is shown that the MCS method with respect to nonlinear situations surely comes to very effective method to the uncertain parameter effects on the response evaluations for the offshore structure. Since the uncertain parameters give the important contributions on the maximum response evaluations, it is essential for the reliable design of the offshore structure to make the uncertainty effects clearly with respect to the response.