臺灣博碩士論文加值系統

本文以水彈性力學理論，以模態疊加法計算船體與波浪間的水彈性耦合作用，考量波浪負荷造成船體整體變形下的應力分佈情形，並求得船體在單位波高下的應力響應函數(Response Amplitude Operator, RAO)；利用頻譜疲勞分析法，針對船體應力集中區域，將海洋頻譜轉換為船體負荷應力頻譜，探討波浪作用下，水彈性力學之流固耦合現象，對船體結構疲勞損傷及壽命的影響。
船舶航行時，承受輕船重量、貨物壓載及海水壓力等靜態負荷，亦承受海浪不規則反覆作用的動態負荷；而動態負荷造成應力振幅的變動，係船體結構產生疲勞損傷的主因；加上近年來，由於船舶大型化及輕量化，使得剛體(Rigid Body)效應式微，船體自然振動頻率大幅降低，趨近至船舶與波浪的遭遇頻率區間，受流固耦合之共振影響，造成船體波振(Springing)現象明顯，引起額外的應力變動，導致因疲勞損傷而發生的海難事件層出不窮，故船體疲勞強度已成為新船結構設計的評估重點之一
本文計算工具採用法國驗船協會已開發之分析軟體，配合其訂定的頻譜疲勞分析基準及流程，包含S-N Curve及累積損傷法則的選定，以台灣國際造船公司所設計8,240 TEU貨櫃輪為參考船，針對容易產生疲勞損傷的應力集中區域進行頻譜疲勞分析，評估水彈性力學對疲勞壽命的影響程度，期待將本研究成果，做為日後設計大型貨櫃輪時，評估其疲勞壽命及尋求設計改善對策之依據。

In accordance with hydro-elastics (HE), this study uses the modal superposition method to examine the hydro-elastic effect from the interaction between ships and waves and the stress distribution of different deformations under a wave load. The study obtained the stress response amplitude operator (RAO) of stress concentrating area to transfer wave spectrum to structure stress spectrum, and then assessed structural fatigue damage and life.
A ship sailing on the sea is not only exposed to static pressure from water and weight of the ship and cargo but also dynamic load such as cycle-loading of irregular waves. The dynamic load will cause stress variations on ships and result in fatigue damage. In recent years, ships have become larger and lighter; thus, the rigid body effect has become much weaker. Because of the new materials and models used in ships, the springing phenomena has become more obvious and significantly reduced the natural frequency of the ship. This lower frequency can vibrate with the wave environment and cause increased vibrations in the ship. In consequence, the lower frequency causes extra stress variation. Ships are often wrecked due to fatigue damage; therefore, the assessment of fatigue strength in ship structures has become an important point of analysis in the ship designing process.
The analysis software and spectral fatigue analysis (SFA) process were developed by the Bureau Veritas classification society (BV). The reference ship was a 8,240 TEU container ship, which was built by CSBS Corp., Taiwan and used for the fatigue damage assessment and spectral fatigue analysis.

誌謝............................................................................................................................... i
中文摘要...................................................................................................................... ii
ABSTRACT ................................................................................................................iii
目錄............................................................................................................................. iv
圖目錄........................................................................................................................ vii
表目錄......................................................................................................................... xi
符號表........................................................................................................................ xii
第1章緒論 ……………………………………………………………………………1
1-1 前言 ............................................................................................................... 1
1-2 研究動機........................................................................................................ 1
1-3 分析方法........................................................................................................ 2
1-4 文獻回顧........................................................................................................ 3
第2章船舶水彈性力學分析方法............................................................................. 5
2-1 擬靜態之水動力分析 .................................................................................... 7
2-1-1 擬靜態分析理論................................................................................. 7
2-1-2 求解邊界值問題................................................................................. 9
2-2 水彈性力學之水動力分析........................................................................... 11
2-2-1 水彈性力學之結構響應.................................................................... 11
2-2-2 水動力分析....................................................................................... 14
2-3 計算分析流程與軟體 .................................................................................. 23
第3章疲勞壽命分析理論 ....................................................................................... 25 iv
3-1 疲勞壽命預估方法 ...................................................................................... 25
3-1-1 簡易計算法....................................................................................... 25
3-1-2 正規頻譜分析法............................................................................... 26
3-2 結構應力評估.............................................................................................. 27
3-2-1 公稱應力(Nominal stress) ................................................................. 28
3-2-2 熱點應力(Hot spot stress).................................................................. 29
3-2-3 缺口應力(Notch Stress)..................................................................... 36
3-3 S-N Curve ..................................................................................................... 37
3-3-1 S-N curve的選擇.............................................................................. 37
3-3-2 S-N curve與Notch應力之關係....................................................... 41
3-4 疲勞壽命評估.............................................................................................. 42
3-4-1 海洋波之波浪頻譜............................................................................ 43
3-4-2 應力響應頻譜................................................................................... 46
3-4-3 成份波之波高的機率密度與分佈.................................................... 47
3-4-4 短期分佈........................................................................................... 49
3-4-5 長期分佈........................................................................................... 50
3-4-6 短期應力評估................................................................................... 52
3-4-7 長期疲勞評估................................................................................... 53
第4章貨櫃輪疲勞壽命之實例分析........................................................................ 55
4-1 基本資訊...................................................................................................... 55
4-2 參考船基本資料.......................................................................................... 57
4-3 遭遇之波浪.................................................................................................. 58 v
4-3-1 波浪散佈圖(Wave Scatter Diagram).................................................. 58
4-3-2 波浪頻譜........................................................................................... 58
4-3-3 波浪航向角(Wave Heading).............................................................. 59
4-3-4 波浪頻率........................................................................................... 61
4-3-5 負載狀況........................................................................................... 61
4-4 船體分析模型.............................................................................................. 62
4-4-1 結構模型........................................................................................... 62
4-4-2 水動力模型....................................................................................... 66
4-4-3 積分模型........................................................................................... 67
4-5 實例分析...................................................................................................... 68
4-5-1 擬靜態分析....................................................................................... 68
4-5-2水彈力分析........................................................................................ 88
4-5-3頻譜疲勞分析.................................................................................... 96
第5章結論與展望................................................................................................. 106
5-1結論............................................................................................................ 106
5-2展望............................................................................................................ 107
參考文獻.................................................................................................................. 109

[1] Heller S R and Abramson H N, “Hydroelasticity：A new naval science[J]”, Journal of American Society of Naval Engineers, 71(2), pp.205-209, 1959.
[2] Bishop, R.E.D. and W.G. Price, “Hydroelasticity of Ship”, Cambridge University Press, 1979
[3] Bishop R E D, Price W G and Wu Y S, “A general linear hydroelasticity theory of floating structures moving in a seaway”, Phil, Trans, Royal, Soc, London, A316, pp.375-426, 1986.
[4] Yousheng Wu, “Hydroelasticity of floating bodies, Brunel University”, 1984.
[5] Hirdaris S E, Price W G and Temarel P, “Two- and three-dimensional hydroelastic modelling of a bulker in regular waves”. Marine Structures, 16(8), pp.627-658 2004.
[6] Ming Kang Wu and Torgeir Moan, “Linear and Nonlinear Hydroelastic Analysis of High-Speed Vessels”, Journal of Ship Research, Vol.40, No.2, pp.149-163, 1996.
[7] Xia, J. and Z. Wang, “Time Domain Hydroelasticity Theory of Ships Responding to Waves”, J. of Ship Res., Vol. 41/4, pp.286-300, 1997.
[8] Jensen, J.J. and Z. Wang, “Wave Induced Hydroelastic Response of High Speed Monohull Displacement Ship”, 2nd Int. Conf. on Hydroelasticity, Fukuoka, Japan, 1999.
[9] Rao T A, Iyer N R and Rajasankar J, “Dynamic response analysis of ship hull structures”, Marine Technology, 37(3), pp.117-128, 2000.
[10] Chen, X.B., B. Molin and F. Petitjean, “Numerical evaluation of the springing loads on tension leg platforms”, Marine Structures, , pp. 501-524, 1995.
109
[11] Malenica, S., Tuitman, J.T., Bigot, F. and Sireta, F.X., “Some Aspects of 3D Linear Hydroelastic Models of Springing”, In P. Ferrant & XB Chen (Eds.), pp. 529-538. La Chapelle sur Erdre, France: ICHD2008 Local organizing committee, 2008.
[12] Kazuhiro Iijima a, Tetsuya Yao a, Torgeir Mo, “Structural response of a ship in severe seas considering global hydroelastic vibrations”, 2008.
[13] Senjanovic, I., Malenica, S. and Tomasevic, S., “Investigation of ship hydroelasticity”, Ocean Engineering 3 , pp. 23-535, (2008a).
[14] 田超，吴有生，” 船舶水弹性力学理论的研究进展”， 上海交通大学船舶，海洋与建筑工程学院，上海，2008。
[15] 第216研究協會,“大型船縱向骨材強度之研究成果報告書”,財團法人日本造船研究協會,平成6年3月。
[16] Bureau Veritas, “Manual of Starspec” , 2010.
[17] 凌志榮，“雙層船殼超大型油輪之疲勞強度分析”，台灣大學造船暨海洋工程研究所碩士論文，民國88年。
[18] 張志鴻，“對接焊道缺陷之散裝貨輪疲勞強度研究”，台灣大學造船及海洋工程研究所碩士論文，民國90年。
[19] 劉仲益，“貨櫃船疲勞壽命強度之探討”，台灣大學造船暨海洋工程研究所碩士論文，民國84年)。
[20] 廖飛揚，“貨櫃船疲勞壽命預估方法之探討”，台灣大學造船及海洋工程研究所，民國84年。
[21] 謝靜如，“以共同結構規範分析雙層船殼油輪疲勞強度之研究”，台灣大學工程科學及海洋工程學研究所，民國99年。
110
[22] 蔡思潔，“以共同結構規範分析雙層船殼油輪疲勞強度之研究” ， 台灣大學工程科學及海洋工程學研究所，民國101
[23] Moskowitz, L., “Estimates of the power spectrums for fully developed seas for wind speeds of 20 to 40 knots.” J. Geophys.Res., 69, 5161–5179, 1964
[24] Pierson, W. J., “The interpretation of wave spectrum in terms of the wind profile instead of the wind measured at a constant height.” J. Geophys. Res., 69, 5191–5203, 1964.
[25] Bretschneider,C.L., “Significant waves and wave spectrum, Ocean Industry”, Feb,pp.40-46. 1968.
[26] K. Hasselmann et al, “Measurements of Wind-Wave Growth and Swell Decay during the Joint North Sea Wave Project (JON SWAP)”, 1973
[27] Timo Kukkanena, Timo P.J. Mikkola, “Fatigue assessment by spectral approach for the ISSC comparative study of the hatch cover bearing pad”, Marine Structures, vol. 17, Issue 1,pp.75-90.,2004.
[28] International Association of Classification Societies, ”Guidelines & recommendation REC_56－Fatigue assessment of ship structures”, 1999.
[29] Inge Lotsberg, Gudfinnur Sigurdsson, “Hot Spot Stress S-N Curve for Fatigue Analysis of Plated Structures”,Transaction of the ASME, pp.330-336, 2006(Vol.128)
[30] Z. HASHIN, A. ROTEM , “A Cumulative Damage Theory of Fatigue Failure”, Material Science and Engineering , 1978 ,pp.147-160.
[31] K.GOLOS, F.ELLYIN, “Generalization of cumulative damage criterion to multilevel cyclic loading”, Theoretical and Applied Fracture Mechanics, pp.169-176, 1987
111
[32] D. Kujawski，F. Ellyin,“A cumulative damage theory for fatigue crack initiation and propagation”
[33] Faltisen, O.M., “Sea loads on ships and offshore structures”, Cambridge Ocean Technology series. Cambridge University Press, 1990.
[34] Salvesen, N., Tuck, E.O. and Faltinsen, O., “Sea Motion and Sea Loads”,Transaction, Vol. 70, SNAME, pp. 250-287, 1970.
[35] Malenica, S., “Hydro structure interactions in seakeeping”, International Workshop on Coupled Methods in Numerical Dynamics, IUC, Dubrovnik, Croatia, September 19th-21st, 2007.
[36] Chen, X.B., “Approximation on the quadratic transfer function of low-frequency loads”, Proc. 7th Intl. Conf. Behaviour Offshore Structures, BOSS’94, 2, pp289-302, 1994.
[37] Chen, X.B., “Hydrodynamics in offshore and naval applications – Part I”, Keynote lecture of 6th Intl. Conf. Hydrodynamics, Perth (Australia)(2004).
[38] Storhaug, G. and E. Moe, “Measurements of Wave induced Vibrations Onboard a Large Container Vessel Operating in Harsh Environment”, Proceedings 10th International Symposium on Practical Design of Ships and Other Floating Structures, 2007.
[39] Tuitman, J.T. and Malenica, S., “Fully coupled seakeeping, slamming, and whipping calculations”, Proceedings of the Institution of Mechanical Engineerings, Part M: Journal of Engineering for the Maritime Environment.
[40] BV_NI393 – Fatigue Strength of Welded Ship Structure.
[41] Longuet-Higgins, M.S., Cartwright, D.E., and Smith,N.D., "Observations of the directional spectrum of sea waves using the motions of a floating buoy," Ocean Wave Spectra, Prentice-Hall,Englewood Cliffs, NJ,1963.
112
[42] Starspec – User Guide (2009)
[43] 13.42 Lecture: Ocean Waves, Alexandra H. Techet, MIT Ocean Engineering, Spring 2005
[44] FEMAP– User Manual(2010)
[45] HOMER – User Manual (2010)
[46] Springing– User Guide (2009)