Session: 06-17-05 AI Technology for Ocean Engineering - V

Submission Number: 182338

Assessment of Long-Term Hull Fatigue Damage Considering Nonlinear Hydroelastic Effects Using a Surrogate Model 

This paper focuses on the calculation of long-term fatigue damage for elastic ships, as wave-induced high-frequency hull vibrations, such as springing and whipping, significantly increase the fatigue damage of hull structures. However, current fatigue damage assessment methods that account for load nonlinearity effects require extensive computation of response time histories under short-term sea states, whether through spectral analysis or rainflow counting. This paper proposes a surrogate model based on Gaussian process regression to accelerate the process. The surrogate model is initially trained using a subset containing only a few typical sea states to establish the mapping between short-term sea states and short-term fatigue damage. Sea states are sampled via the Monte Carlo method, and the surrogate model predicts the hull fatigue damage for these sampled conditions, thereby computing the long-term fatigue damage over the vessel's service life. By progressively supplementing sea states, efficient convergence and accurate calculation of the long-term fatigue damage are achieved. Compared to traditional approaches, the proposed surrogate model improves computational efficiency for long-term fatigue damage and adequately accounts for the variability of short-term sea states. A comparative study is conducted on a 20,000 TEU container ship, where the long-term fatigue damage is computed using both traditional assessment methods and the proposed surrogate model method. The results validate the advantages of the presented method.

Presenting Author: Jian Zou Harbin Engineering University

Presenting Author Biography: Assistant Researcher at the School of Ship Engineering, Harbin Engineering University, engaged in ship wave load forecasting and ship structural strength assessment。

Authors:

Jian Zou Harbin Engineering University
Hui Li Harbin Engineering University
Ruixiang Liu Harbin Engineering University