Sensitivity approach for modelling the environmental loading of marine structures through a matrix response surface

The actual challenge for the reassessment of existing offshore structures through a rational process of reassessment leads one to state the importance of a response surface methodology. At different steps along the quantitative analysis, quite a number of approximations are developed as surrogates for the original model. They require subsequent uncertainty and sensitivity studies. This paper suggests a geometrical description of the energy of the wave kinematics fields for the building of a wave loading response surface. The matrix response surface of the water particle kinematics field is shown to be suitable for further transfers and for uncertainty and sensitivity studies. This allows discussion of the complexity level to be introduced in stochastic modelling of the wave actions within its relevance for the probabilistic mechanics analysis of offshore structures. For illustration, in situ measurements are used to provide ranges and distributions of basic variables with a view to performing uncertainty and sensitivity studies.