碩士 / 國立海洋大學 / 造船工程學系 / 87 / Under a ship''s service life, the hull structure is mainly subjected to wave loads, which is cyclic and therefore can cause fatigue cracks in the structure. In order to make the assessment of fatigue strength of ship structures, a analysis system is established, consisting of the following three parts:
1. Three dimensional analysis of ship motions in waves and the wave loads;
2. FEM-analysis of structural responses due to the fluid-structure interaction;
3. Fatigue life analysis of the structure details due to high stress level.
Since two different computer codes are used for the wave load calculation and structural analysis respectively, an interface program is developed within the scope of this work so that the wave-induced hydrodynamic pressures over the hull surface can be easily transferred into nodal loads for the structural analysis.
In this paper, a boundary element method based on Green''s function is applied for calculation of ship motions in waves and wave loads. The result shows a good agreement with the model measured. After having calculated the stress transfer functions at some hot pots in the ship structure, the short-term stress distributions can be obtained for different wave conditions. The long-term stress distributions are then calculated based upon the wave statistics around the Taiwan island. Finally, the fatigue life of the structure details is estimated using the relevant S-N curves according to the Miner''s cumulative damage rule.
| Identifer | oai:union.ndltd.org:TW/087NTOU0345001 |
| Date | January 1999 |
| Creators | Chen Tien Li, 陳天利 |
| Contributors | Wei-Hwei Wang, 王偉輝 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 76 |
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