Fatigue characterization analysis of a submerged fishing farm platform through spectral-based fracture mechanics. (15th November 2022)

• Record Type: Journal Article
• Authors: He, Wentao; Xie, Lingjun; Wang, Shuqing; Wang, Changzi; Hu, Zhiqiang; Liu, Jingxi
• Is Part Of: Ocean engineering. Volume 264(2022)
• Publication Date: 2022-11-15
• Subjects: Fracture mechanics -- Crack propagation -- Remaining fatigue life -- Spectral analysis -- Fishing farm platform; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2022.112351
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: This study proposes a general direct calculation approach for fatigue crack growth evaluation and life predictions through a spectral-based fracture mechanics method. First, equivalent damage accumulation rates are introduced to describe the crack propagation characteristics under short-term sea states, integrating wave spectrum and fracture mechanics. Subsequently, a general fatigue crack growth program is integrated to realize automatic crack growth, accurate stress intensity factor (SIF) calculation and reliable fatigue life prediction through coupling analysis of meter-scale structures and millimeter-scale cracks. Finally, a parameter study is implemented to explore the influence of wave direction and initial crack size/shape on the fatigue performance of the fishing farm platform. Results indicate that the remaining fatigue life is evidently longer under 90° wave direction than that under 0 and 45°, which can be well characterized through SIF transfer functions. Critical fatigue life decreases with the increase of crack size and aspect ratio with the shortest duration of 12.8 years, demonstrating that residual fatigue life is closely associated with initial crack state. Fatigue failure is more predominant at lower tubular joints with the critical fatigue life ranging from 15 to 30 years, indicating the self-developed program possesses good universality and applicability in dealing with fatigue issues. Highlights: A universal program (FCG-system) is integrated for fatigue life prediction utilizing spectral-based fracture mechanics. Equivalent damage accumulation rate is introduced to simplify the crack propagation characteristics. Remaining fatigue life of a fishing farm platform is investigated through SIF transfer function. Parameter study is implemented to study the influence of wave direction and initial crack size/shape. FCG-System owns good universality and applicability in dealing with fatigue problems.