A Rayleigh distribution-based fatigue damage prediction model for offshore structures under bimodal responses

作者：Haiyang Ge, Xiaozhou Guo, Xin Li, Qiangqiang Wei, Bo Wu · 发表于：Ocean Engineering · 年份：2025 · DOI：10.1016/j.oceaneng.2025.122290 · 被引用次数：3 · 研究领域：Structural Integrity and Reliability Analysis、Fatigue and fracture mechanics、Material Properties and Failure Mechanisms

Offshore structures frequently exhibit bimodal responses composed of distinct low-frequency (LF) and high-frequency (HF) components, which present significant challenges for accurate fatigue damage prediction. To address this challenge, a novel fatigue damage prediction model is proposed, specifically designed for bimodal responses involving two well-separated Gaussian random processes. The proposed model accounts for the nonlinear superposition between these processes and is developed based on the Rayleigh distribution. A parameter search strategy is established to identify the spectral characteristics and determine key parameters, including damage contribution coefficients ( R 1 , R 2 ), power coefficients ( P 1 , P 2 ), and coupling coefficients σ . The prediction performance of the model is evaluated using a newly developed bimodal spectrum and material properties ( k = 3, 4, and 5) of three representative offshore steels. Furthermore, the proposed model is compared with several typical prediction methods, using high-confidence rain-flow counting (RFC) solutions as benchmarks. The results demonstrate that the proposed model achieves robust predictive stability and accuracy under bimodal responses, with particularly significant improvements in wideband regions.