博士 / 中正理工學院 / 國防科學研究所 / 87 / Owing to the diverse nature of different missions a submarine often floats on the water surface and dives underwater. The cyclic hydrostatic pressure loading causes a fatigue problem of the submarine pressure hull. The Guppy-Class submarine of the ROC navy has been employed for more than five decades, thereby increasing the likelihood of fatigue at the pressure hull greatly. Therefore, how to accurately estimate the fatigue life of the submarine pressure hull as a valuable reference for maintenance or construction stage is of relevant interest. For this reason, this work presents a novel means of estimating the fatigue life of a submarine pressure hull.
Analytical ability of the finite element method is initially established to designate where the high stress area of the pressure hull is and the strain spectrum of this area under the cyclic hydrostatic pressure loading is obtained. The Coffin-Manson nonlinear experience equation in strain-life method is then applied and combines the Miner damage accumulation rule by using the front strain spectrum. In doing so, the fatigue life estimation schedule is constructed. In this schedule, the Rainflow counting method and Newton-Raphson method are used to simply the diving load history and derive the Coffin-Manson nonlinear experience equation.
Comparing our results with those of Julie*s verifies the effectiveness of the fatigue life estimated schedule. These results are obtained from the experimental fatigue life for a plate with the circular hole under ten sets of different load spectra. This phenomenon reveals that the likelihood and accuracy of the fatigue life estimated by this schedule is closely to the experiment results. Finally, the Guppy Class submarine of the ROC navy is used as an illustrative example to predict its fatigue life. According to our results, the high stress area on the Guppy Class submarine pressure hull often occurs in the man access boundary located in an afterward battery room. If only considering the opening of the pressure hull, the estimated fatigue life of the Guppy Class submarine pressure hull is years. While considering a situation in which the cylindrical shell stiffened the man access hole, the estimated fatigue life of the Guppy Class submarine pressure hull is years. As conservative estimate, the fatigue life is years. If the submarine employed in one year is six months of navigation and six months in ports, the fatigue life of the Guppy-Class submarine is years.
The fatigue life estimated schedule developed herein can provide the submarine pressure hull structure designer and operator with an effective tool at design or periodical maintenance stage. Estimation results obtained from the schedule can also provide a valuable reference for renovating the Guppy-Class submarine.
| Identifer | oai:union.ndltd.org:TW/087CCIT0584001 |
| Date | January 1999 |
| Creators | Ching-Yu Hsu, 徐慶瑜 |
| Contributors | Cho-Chung Liang, 梁卓中 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 174 |
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