Session: 15-09-01 Marine Environment and Offshore Structure Design under Climate Changes

Submission Number: 181709

Application of Mixture Distribution-Based Environmental Contours to Marine Structure Design 

Environmental Contour (EC) holds significant importance for the design of marine structures, and it is frequently utilized to identify extreme sea states and assess potential damages to structures. The construction of EC can be achieved by integrating the Inverse First Order Reliability Method (IFORM) with joint probability techniques for metocean variables. This study aims to capture the complex dependence structure within metocean data using an appropriate and flexible statistical model. In the research, the Gaussian mixture distribution was employed to model both the marginal and bivariate distributions of environmental variables. The optimal number of components in the mixture model was determined via the Bayesian Information Criterion (BIC), while the Expectation-Maximization (EM) algorithm was used to estimate the multiple unknown parameters in the model. Subsequently, the validity of the joint mixture model was verified through statistical tests. Furthermore, the ECs generated by the Gaussian mixture model were compared with those constructed by the commonly used conditional Weibull-Lognormal model. The results demonstrate that the Gaussian mixture model exhibits excellent performance in fitting wave data from different sites and handling contours with highly complex probabilistic characteristics, thus confirming its robustness. These optimized ECs show great potential in evaluating the most probable extreme responses of marine structures, which in turn can enhance the safety and reliability of marine engineering designs.

Presenting Author: Yuliang Zhao State Key Laboratory of Coastal and Offshore Engineering, Ocean University of China

Presenting Author Biography: Name: Yuliang Zhao
Department: Ocean Engineering Department
Address: No.1299 Sasha Road, Qingdao,
P. R. China, 266100
Cell Phone: +86-18562592605
E-mail: zhaoyuliang@ouc.edu.cn
Education:
1. 2016/09–2022/06, Ocean University of China, Harbor, Coastal and Offshore Engineering, Ph.D.
2. 2012/09–2016/06, Ocean University of China, Naval Architecture and Marine Engineering, Bachelor Degree.
Work Experience:
1. 2022.07 –Now, Work in, Engineering College, Ocean University of China

Authors:

Yuliang Zhao State Key Laboratory of Coastal and Offshore Engineering, Ocean University of China
Peng Zhang China Renewable Energy Engineering Institute
Dazhou Geng China Renewable Energy Engineering Institute
Yu Xu State Key Laboratory of Coastal and Offshore Engineering, Ocean University ofChina
Zhi-Ming Yuan Department of Naval Architecture, Ocean and Marine Engineering, University of Strathclyde