Extreme response predictions of nonlinear compliant offshore structures by stochastic linearization

Abstract This paper describes a procedure for extending standard stochastic linearization to establish linearization methods that are better suited for the purpose of predicting extreme responses. The standard method of linearization applied to a nonlinear dynamic system is based on a mean-square deviation measure to derive the ‘equivalent’ linear system. Experience indicates that the obtained linear system may have approximately the same mean-square response as the original nonlinear system. For predicting extreme response this procedure is not, however, equally suitable. In the case of strong nonlinearities in the dynamic model, application of the standard method of linearization may lead to substantial overestimation of extreme responses. It is shown by example studies that the proposed methods may offer significant improvement in the ability to predict extreme responses.