Journal
OCEAN ENGINEERING
Volume 230, Issue -, Pages -Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.oceaneng.2021.109021
Keywords
Structural reliability; Vine copula; Probability of failure (Pf); Limit state function (LSF)
Funding
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Canada Research Chair (Tier I) Program in Offshore Safety and Risk Engineering
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This study proposes a framework for reliability assessment of ocean structural systems using vine copula to capture variable dependence, showcasing its superiority over Gaussian coupling assumption and statistical independence in modelling complex marine systems. The developed method shows closer probability of failure results to the reference Importance Sampling results.
For an improved estimation of marine structural reliability, a consideration of random variable dependency is essential. With a limited study on dependence modelling of marine structures, this study proposes a framework for reliability assessment of ocean structural systems with multidimensional variables. This framework captures possible nonlinearity and tail dependence in the variables using vine copula. The proposed method develops a graphical structure of random variables consisting of nodes, edges, and trees using the Drawable Vine (D-vine) approach. This study demonstrates the developed framework on a jacket support structure subjected to the extreme environmental load conditions at Jeanne D' Arc basin on Canada's east coast. The structure's reliability is evaluated with optimally selected copulas in the D-vine trees and associated marginal distributions. A comparison between the reliability result using the D-vine copula method, Gaussian coupling assumption, and statistical independence between variables proved its superiority in modelling variable dependence of complex marine systems. The probability of failure (Pf) using D-vine copula was closer to the reference Importance Sampling (IS) results than other methods.
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