部分充水艙間沖激現象對船舶抗撞性能之影響

艙間未充滿水的自由液面因艙體運動產生晃動而造成艙壁週期性的沖激壓力稱為沖激現象(Sloshing) ，它是一種非常複雜的流體運動。當船艙間部分充水時，自由液面會隨著船體運動而晃蕩拍擊艙壁，若船舶發生破撞時，其沖激力與沖激週期對船舶抗撞性能可能會有影響；近年來國際上對海洋環境保護與海洋維護以及對人員安全的重視，為使船舶事故發生所引發損傷降到最低，在船舶抗撞結構與航行安全有特別考量。本文探討船舶艙間部分充水對船舶抗撞性能的影響；主要內容為分析部分充水的水箱在給定速度變化下，自由液面晃動的沖激現象，並將其流體週期性沖激力以等效質量-彈簧-阻尼系統代替，以簡化問題模型，並應用於8,000 TEU貨櫃船機艙段遭受同級貨櫃船側向撞擊過程的結構損壞與衝擊狀況，以等效「彈簧-質量-阻尼」系統代替部份充水艙間的水面沖激效應之吸能與沖激力效應，比較5種不同艙間充水狀況在碰撞後，撞擊船之船艏與被撞船之機艙段產生的破壞狀況。本研究以LS-DYNA非線性有限元素程式進行船舶碰撞分析，分析結果顯示船側艙間局部充水沖激效應可吸收部分能量，可提高被撞船抗撞能力，降低撞擊破壞程度。但船艏艙間局部充水無法增加被撞船的抗撞能力。

關鍵字

自由液面；沖激現象；等效質量-彈簧-阻尼模型；船舶碰撞；抗撞能力

並列摘要

The sloshing phenomenon is a flow impact inside a fluid tank with a free surface and is a very complicated fluid dynamics problem. Partial filled fluid tank in ship will induce sloshing effect to impact the tank periodically when the ship is in time varied motion. In order to protect the ocean environment and to promote the crew's safety, as well as to minimize and damage after accident, some designs for anti-collision has been taken into consideration. In this paper, the sloshing effect of the partially filled fluid tank in container ships on the crashworthiness in ship collision was investigated. The sloshing impact in the rectangular tank was analyzed. And an equivalent mass-spring-damper system model to simulate the periodic sloshing impact induced by specified has been derived. The 8000 TEU container ship with partially filled fluid tank was selected as case .The structural damage and the crashworthiness of structures for container ship's bow striking the engine room section of the 8000TEU container ship have been investigated. The structural damage among five partially filled conditions after striking were compared. The LS-DYNA nonlinear finite element analysis program was used to analyze the ship collision in the paper. The results show that the partial filled fluid in side tank can improve the crashworthiness of struck the ship structures. On the contrary, the partial filled fluid in bow tank can not improve the crashworthiness of struck the ship structures.

並列關鍵字

sloshing ； equivalent spring-mass model ； ship collision ； crashworthiness

參考文獻

[4] Wierzbicki T., 1995, “Crushing damage of web girders under localized static loads”, pp.199-235, Journal of construction steel research 33th, 1995.

[6] Kitamura O., 2002, “FEM approach to the simulation of collision and grounding damage,” pp.403-428, Marine Structures 15th, 2002.

[7] Tornqvist R., 2003, “Design of crashworthy ship structures,” Maritime Engineering. Department of Mechanical Engineering, Technical University of Denmark, 2003.

[8] 黃萬偉，2005，船舶結構遭錐狀體撞擊時的撕裂破壞之研究，國立台灣大學工程科學及海洋工程研究所碩士論文， 2005。

[9] 陳建邦，2007，船舶雙層殼結構抗撞能力估算法分析，國立台灣大學工程科學及海洋工程研究所碩士論文，2007。

國際替代計量

部分充水艙間沖激現象對船舶抗撞性能之影響

全文下載

主題瀏覽