Response Spectrum Estimation for Fixed Offshore Structures With Inundation Effect Included: A Price’s Theorem Approach

Instead of a Volterra-series based method, a method based on Price’s theorem and Fourier Transforms is proposed for evaluating the nonlinear response power spectra of fixed offshore structures modeled as finite-memory systems. The numerical computation effort required for spectral estimations using the proposed method is significantly less than that of the Volterra-series method that requires multi-dimensional integrations. Nonlinear frequency-domain analyses of two jack-up platform structures are carried out to study the effects of inundation, cubic and quartic drag terms and polynomialization methods.