ABSTRACT

The concept of stochastic dynamic response is elaborated by introducing the “sample” approach, which allows the connection with time-domain response analysis methods based on deterministic methods to be made. By repeating the response analysis for a number of sample functions, the statistical properties of the corresponding response processes can be established. Methods for dynamic response analysis in the frequency domain are also outlined as well as the probability domain approach based on the Fokker-Planck equation. Furthermore, a number of different mechanical limit states which are relevant for design of marine structures are addressed. These limit states mainly belong to one of the following categories of criteria: Serviceability limit state (SLS), Ultimate limit state (ULS), Fatigue limit state (FLS) and Accidental limit state (ALS). Focus is on the Ultimate and Fatigue limit states (i.e. ULS and FLS). For these limit states, efficient and sufficiently accurate numerical methods are in demand for calculation of extreme load and response, as well as for estimation of fatigue damage.The so-called contour-line methods are described within this context. There are typically different design documents for bottom-fixed versus floating (including compliant) systems. Such differences are discussed in relation to different sets of codified rules.