Multivariate Gaidai reliability methodology for marine riser dynamics in the Red Sea with memory effects included

Marine risers and umbilicals being utilized extensively within the offshore industrial sector, mainly for oil transport from drilling location at seabed to the mother vessel/platform; however, they are often exposed to excessive dynamic environmental and operational loads. Excessive loading on marine risers may increase both fatigue damage and instantaneous structural collapse damage, creating additional operational risks. For operating offshore structures employing marine risers, design requires an accurate prediction of the riser dynamics, under the influence of in-situ ocean/sea currents and consequent hydrodynamic VIV (i.e., Vortex-Induced Vibrations) loads. In the current study, an experimental riser dynamics dataset had been utilized, representing marine riser's hydrodynamics under realistic currents load pattern. Current study proposes a novel robust multimodal structural reliability methodology, based on the raw measured dataset. The bivariate modified Weibull-type method had been briefly introduced. It had been concluded that the bivariate modified Weibull-type method is capable of considering realistic environmental inputs and delivering robust and accurate predictions. Multivariate state-of-the-art Gaidai reliability methodology had been utilized to cross-validate bivariate predictions, it had been shown that multivariate approach offers more accurate design values predictions than bivariate one. The adopted multimodal reliability methodology may be utilized within contemporary marine riser design phase to optimize riser/umbilical structural characteristics, thereby limiting potential structural and environmental damages. Regarding the potential future applications of marine risers and their reliability analysis, one may mention deep-sea mining.