关键词: 舱口角隅, 裂纹扩展路径, 谱分析, 断裂力学, 疲劳寿命

Abstract: Hatch corner is a typical stress concentration area in a large opening ship, and is a crucial structure detail for fatigue assessment. In this paper, an elliptic hatch corner ahead of the cabin in an ultra large container ship was taken as an example to research the assessment of the fatigue life of hatch corner based on the spectral analysis and fatigue crack growth method. Firstly, the hydrodynamic and structural response analysis were performed to get the whole ship’s structural responses and the stress distribution in the hatch corner under different loading conditions, and then determine the possible crack initiation positions on the hatch corner. Secondly, the analysis results were taken as boundary conditions of FE hatch corner model with crack which is built via ANSYS, SIF (Stress Intensity Factor) was obtained. Taking the maximum circumferential stress criterion (MCSC), propagation paths of crack in the hatch corner under different load cases were gotten, then regression was used to establish a corresponding empirical formula of SIF based on a large series of analysis. Finally, the spectral analysis approach recommended by ABS was adopted to construct the fatigue load spectrum, and the Single Curve Model and the proposed empirical formula were used to predict the fatigue life of the hatch corner. The results could provide a reference for fatigue assessment of hatch corner.

Key words: hatch corner, crack propagation paths, spectral analysis, fracture mechanics, fatigue life