Non-linear restoring forces of an offshore platform

Abstract

The method of calculation of non-linear restoring forces presented in this paper is simple, concise and feasible to apply easily in the calculation of restoring forces of platforms in order to simulate motion responses of offshore platforms in the time-domain. In this method, hydrostatic restoring forces and moments are related to the translational and/or rotational displacements. Calculations of non-linear yaw, roll and pitch restoring moments are based on the catenary type of moorings. Although the method presented here is a simple one, it is capable of the calculation of restoring forces for use in the time-domain motion simulations of offshore platforms, with an acceptable degree of accuracy when the numerical simulation results were compared with the experimental measurements.