An efficient importance sampling method for long-term fatigue assessment of deepwater risers with time domain analysis

Gao, Yidan; Low, Ying Min

doi:10.1016/j.probengmech.2016.04.003

Cited by 15 publications

(6 citation statements)

References 17 publications

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“…The static behavior analysis is of highly deformed risers were carried out successively by Chucheepsakul and Monprapussorn (2000), Karunakaran et al (1999) and Santillan and Virgin (2011). The vortex-induced vibration responses of marine riser were investigated by Xue et al (2015) and Gao and Low (2016) through numerically simulating and theoretical analysis. Ge et al (2019) presented a method for the fatigue analysis of marine risers.…”

Section: Introductionmentioning

confidence: 99%

RETRACTED ARTICLE: Dynamic boundary of floating platform and its influence on the deepwater testing tube

He¹,

Guo

et al. 2020

European Journal of Remote Sensing

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The motion of the floating platform is one of the important factors influencing the safety of testing string. The allowable motion limits of various floating drilling platforms are discussed and their calculation formulas are presented, based on which the nonlinear dynamic response characteristics of the testing tube are investigated through ABAQUS software. Results show that an excessive offset of floating platform will cause many problems to testing tube, such as operation difficulty in rising and landing pipe string, disconnection difficulty of testing tree in case of emergency. Under heave motion and slow drift motion condition, the maximum Mises stress appears in the part closed to the upper end. The heave and horizontal motions of the platform have a superposition influence on the axial force of the pipe. So, a more precise dynamic theoretical model should be developed to study the longitudinal-transverse coupled vibration of testing string in the future.

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Section: Introductionmentioning

confidence: 99%

RETRACTED ARTICLE: Dynamic boundary of floating platform and its influence on the deepwater testing tube

He¹,

Guo

et al. 2020

European Journal of Remote Sensing

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“…Several numerical approaches can be applied to solve the cumulative probability integration, such as Monte Carlo simulation and the importance sampling method. 2,27,28 In general, the direct integral method to compute equation (1) is computationally expensive because all sea states are required to be considered and the corresponding response rule is unambiguous.…”

Section: Assessment Of Long-term Performance Of Mooring Systemsmentioning

confidence: 99%

Long-term extreme response analysis for semi-submersible platform mooring systems

Zhao

Dong

2020

Proceedings of the Institution of Mechanical Engineers, Part M:

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The accurate assessment of long-term extreme responses of floating-structure mooring system designs is important because of small failure probabilities caused by long-term and complex ocean conditions. The most accurate assessment would involve considering all conceivable sea states in which each sea state is regarded as a stochastic process and performing nonlinear time-domain numerical simulations of mooring systems to estimate the extreme response from a long-term analysis. This procedure would be computationally intensive because of the numerous short-term sea states involved. Here, a more feasible approach to evaluate the long-term extreme response is presented through immediate integration combined with Monte Carlo simulations. A parameter fitting procedure of the short-term extreme response distribution under irregular wave conditions is employed to solve the long-term response integration. Case studies were conducted on a semi-submersible platform using environmental data measurements of the Gulf of Mexico and a joint distribution model of the environmental parameters was considered. This approach was observed to be effective and the results were compared with those of traditional methodologies (univariate extreme value design and environmental contour methods). The differences were reflected using a reliability analysis of mooring lines, which indicated that the design standards must be stricter when using long-term analysis.

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“…Monte-Carlo methods are usually used to generate pseudo-random samples from complex distributions [26,46]. Latin Hypercube Sampling (LHS) as a more efficient way can also be applied to generate samples [47,48]. Both of these methods were used herein to validate the JPDFs.…”

Section: Model Diagnostics and Validationmentioning

confidence: 99%

Directional dependence of extreme metocean conditions for analysis and design of marine structures

Haghayeghi

Imani

Karimirad

2020

Applied Ocean Research

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Marine structures are typically sensitive to the direction of wind and waves, especially in extreme metocean conditions. The extreme metocean conditions and their associated predicted directions are not easily reachable from traditional design methodologies. In this research, the most probable combinations of different extreme metocean conditions along with their associated direction are predicted for the HyWind Scotland wind farm, Scotland. To achieve this, the Hierarchical Bayesian Modelling approach is applied to define the Joint Probability Distribution Function (JPDF) of four combinations of metocean parameters, including wave direction, wind direction and wind-wave misalignment. The data is provided by the ERA-Interim dataset in 40 years . The JPDFs are composed of a marginal PDF of directional variables (a mixture of von-Mises Fischer distributions) and two conditional JPDFs which are defined to satisfy the periodicity and positivity of distribution parameters. Then, applying the Inverse First-Order Reliability Method (IFORM) to the JPDFs, the Environmental Contours (ECs) for four sets of metocean data are developed. The results show that extreme values obtained from ECs, including directional variables, are higher than the values of traditional linear ECs. The maximum 50-year extreme value of wind speed from the JPDF of wind direction, wind speed and wave height is 2 m/s higher than the same extreme extracted from the JPDF of wind speed, wave height and period. Another important observed point is that the direction at which the extreme of metocean parameters occurs is quite different from their dominant direction of wind rose or the most probable direction of their probability density function. According to the results, it seems for direction-dependent structures; the application of this method may lead to a more realistic presentation of joint occurrence of linear and directional metocean parameters.

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An efficient importance sampling method for long-term fatigue assessment of deepwater risers with time domain analysis

Cited by 15 publications

References 17 publications

RETRACTED ARTICLE: Dynamic boundary of floating platform and its influence on the deepwater testing tube

RETRACTED ARTICLE: Dynamic boundary of floating platform and its influence on the deepwater testing tube

Long-term extreme response analysis for semi-submersible platform mooring systems

Directional dependence of extreme metocean conditions for analysis and design of marine structures

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