Response of Offshore Structures to Random Waves

Abstract

Probability density functions, mean crossing rates, and other descriptors are developed for the quasi‐static and dynamic responses of offshore platforms to wave forces. It is assumed that offshore platforms can be modeled by simple oscillators, the wave particle velocity is a stationary differentiable Gaussian process, Morison's equation can be applied, and wave forces are perfectly correlated spatially. Results show that both the quasi‐static response and the dynamic response of offshore platforms to wave forces are generally underestimated if the drag force is linearized. Estimates are developed for probabilistic characterictics of these responses based on the crossing theory of random processes and time‐discretization of the wave force process. Simulation studies indicate that these estimates are satisfactory.