(3.236.222.124) 您好!臺灣時間:2021/05/13 21:35
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果

詳目顯示:::

: 
twitterline
研究生:李易軒
研究生(外文):Yi-Syuan Li
論文名稱:離岸風力機單樁基座疲勞分析
論文名稱(外文):Fatigue Analysis of Monopile Foundation for Offshore Wind Turbine
指導教授:林志光林志光引用關係
指導教授(外文):Chih-Kuang Lin
學位類別:碩士
校院名稱:國立中央大學
系所名稱:機械工程學系
學門:工程學門
學類:機械工程學類
論文出版年:2020
畢業學年度:108
語文別:英文
論文頁數:130
中文關鍵詞:離岸風力機單樁基座順序分析法疲勞損傷
外文關鍵詞:offshore wind turbinemonopile foundationsequential approachfatigue damage
相關次數:
  • 被引用被引用:0
  • 點閱點閱:88
  • 評分評分:系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔系統版面圖檔
  • 下載下載:19
  • 收藏至我的研究室書目清單書目收藏:0
疲勞損傷是影響風力發電機壽命之關鍵因素,通常離岸風力機需具備20年之使用壽命,因此有必要計算其在服役期間的疲勞損傷值,確認結構之安全。本研究針對NREL 5-MW離岸風力發電機的單樁基座受到IEC 61400-3之DLC 1.2負載工況及DLC 6.4的負載工況作用,探討風速、潮高、環境負載角度及隨機變數對疲勞損傷的影響,並計算各種負載組合之20年累積疲勞損傷值。
本研究引入順序分析法來計算單樁基座因受到環境負載所產生的響應,包含應力和位移。順序分析法的流程為在BLADED軟體建立完整的模型及環境條件,並且施加所選定的負載工況,求得基樁與塔架連接處受力的動態響應,隨後運用於ANSYS軟體計算單樁的應力和位移。完成順序分析法後會得到基樁各節面的應力歷時,針對此不規則的應力歷時,利用MATLAB軟體及雨流法計算不等振幅疲勞負載之循環數,並使用DNVGL-RP-C203所提供之S-N曲線與Goodman方程式求得對應之疲勞壽命循環數,最後使用Palmgren-Miner Rule計算疲勞損傷值。
模擬結果顯示,針對20年持續發電運轉條件下,在各負載組合中,單樁基座的疲勞損傷最大值皆發生在單樁底部,原因乃類似懸臂樑結構受側向負載時,固定端會有最大的應力。WS6 (13.60 m/s)和WS7 (14.96 m/s)二個風速值會造成水平面以上的單樁結構有較大疲勞損傷,其原因為在接近額定風速時,風機會產生最大之響應。整體而言,風速WS11 (23.12 m/s)會造成單樁底部具有最大疲勞損傷,因為其產生的浪流負載較大。在基樁各節面發生最大疲勞損傷的位置與環境負載施加方向和機艙方向有關,但浪流負載較大之負載組合的施加方向將主導最大疲勞損傷發生的位置。潮位較高的負載組合會誘發較大的疲勞損傷,因為其較大的水壓會產生較大的水動力。而不同隨機變數對於疲勞損傷的影響不大,亦即不同的隨機變數會產生接近的疲勞損傷值,此乃風況頻譜在不同隨機變數下是相同的,代表風力是具有相近的能量。整體而言,本研究所探討的離岸風力機之單樁基座,其最大累積疲勞損傷值在三組不同隨機變數的環境負載作用下,皆遠小於1,顯示此單樁基座可在離岸風力機持續發電20年下或在20年服役期間經歷了待機和運轉階段,都不會因疲勞損傷而失效。上述結果顯示,本研究所建立之分析方法可適用於評估離岸風力機單樁基座疲勞損傷。
The accumulative fatigue damage is a key factor which leads to structural failure of offshore wind turbine (OWT). In general, the lifespan of OWT is expected to reach more than 20 years. Hence, the fatigue damage during the service time should be monitored. Fatigue damage ratio and the structural integrity for the monopile foundation of NREL 5-MW wind turbine are evaluated in this study. The Design Load Cases 1.2 and 6.4 of IEC 61400-3 are applied in this study. For discussing the uncertainties of environmental conditions, various wind speeds, tide heights, wave orientations, and ransom seeds are considered in the analyses.
A sequential approach is introduced to calculate the response of monopile, including stress and deformation. In the first step, the model of 5-MW OWT, environmental conditions, and assigned design situations are specified in the BLADED code. In the second step, ANSYS code is used to calculate the stress/deformation of monopile using the output loading data from the BLADED results. The response from BLADED is extracted and applied in the ANSYS at the interface of tower and monopile. The distributed wind loading is exerted on the monopile above mean sea level (MSL), and the hydrodynamic loading acting on the monopile below MSL is inputted in the ANSYS code. The numbers of cycles for the irregular time histories are calculated using the Rainflow counting method. S-N curve listed in the DNVGL-RP-C203 and Goodman’s approach are employed to determine the corresponding fatigue life for each loading cycle. Palmgren–Miner Rule is finally employed to calculate the cumulative fatigue damage ratio. All of the above calculations related to fatigue damage ratio are performed using the MATLAB code.
The results show that for all of the given loading combinations, the maximum fatigue damage ratio takes place at the bottom section of monopile. Similar to a cantilever beam subjected to lateral loadings, the maximum stress usually occurs at the fixed position. For all the wind speeds investigated, WS6 (13.60 m/s) and WS7 (14.96 m/s) generate greater fatigue damage ratios at the structure of monopile above MSL. As these two wind speeds are close to the rated wind speed, the induced response of wind loading is the largest. Among the given wind speeds, WS11 (23.12 m/s) generates the largest wave loadings and consequently the largest fatigue damage ratio. The location for maximum fatigue damage ratio is influenced by the orientation of rotor-nacelle-assembly and environmental loading. An increase in tide height leads to a greater fatigue damage ratio in the monopile. It is due to a greater hydrodynamic loading caused by the higher water pressure in deeper water. Selection of random seed barely affects the fatigue damage ratio, as a similar wind spectrum and energy is present in the given random seeds. The maximum cumulative fatigue damage ratios calculated for different random seeds are significantly less than 1. It is expected that the given monopile can last for a 20-year non-stop operation for generating power or for a 20-year service time including operating and parking. The overall results demonstrate that the methodology developed in this study is applicable to the assessment of fatigue damage ratio for the foundation of OWT.
LIST OF TABLES VIII
LIST OF FIGURES XIII
NOMENCLATURE XV
1. INTRODUCTION 1
1.1 Introduction to Offshore Wind Turbine 1
1.1.1 Components of offshore wind turbine 1
1.1.2 Type of foundation 3
1.2 External Conditions 6
1.2.1 Wind conditions 6
1.2.2 Marine conditions 10
1.2.3 Other environmental conditions 16
1.3 Literature Review 17
1.3.1 Aerodynamic load 17
1.3.2 Hydrodynamic load 20
1.3.3 Rainflow counting 22
1.3.4 S-N curve and Palmgren-Miner Rule 24
1.4 Purpose 25
2. METHODOS 27
2.1 Sequential Analysis 27
2.2 Dynamic Load Simulation-BLADED 30
2.3 Structural Analysis-ANSYS 38
2.3.1 FEM model in ANSYS 38
2.3.2 Dynamic analysis in ANSYS 41
2.4 Fatigue Design Load Case of 5-MW Offshore Wind Turbine 43
3. RESULTS AND DISCUSSION 50
3.1 Modal Analysis 50
3.2 Fatigue Damage Ratio for DLC 1.2 50
3.2.1 Effects of wind speed and marine parameters on fatigue damage 50
3.2.2 Effects of orientation of environmental loadings on fatigue damage 67
3.2.3 Effects of tide height on fatigue damage 80
3.2.4 Effects of random seed of wind on fatigue damage 90
3.2.5 Comparison of axial stress and von Mises stress 95
3.3 Fatigue Damage Ratio for DLC 1.2 Combined with DLC 6.4 97
4. CONCLUSIONS 101
REFERENCES 104
1. The European Offshore Wind Industry - Key Trends and Statistics 2015, European Wind Energy Association, Brussels, Belgium, 2016.
2. Office of Energy Efficiency and Renewable Energy, The Inside of a Wind Turbine, https://www.energy.gov/eere/wind/inside-wind-turbine, accessed on December 26, 2019.
3. X. Wu, Y. Hu, Y. Li, J. Yang, L. Duan, T. Wang, T. Adcock, Z. Jiang, Z. Gao, Z. Lin, A. Borthwick, and S. Liao, “Foundations of Offshore Wind Turbines: a Review,” Renewable and Sustainable Energy Reviews, Vol. 104, pp. 379-393, 2019.
4. The European Offshore Wind Industry - Key Trends and Statistics 2013, European Wind Energy Association, Brussels, Belgium, 2014.
5. The European Offshore Wind Industry - Key Trends and Statistics 2014, European Wind Energy Association, Brussels, Belgium, 2015.
6. P. Passon, K. Branner, S. E. Larsen, and J. Hvenekær Rasmussen, “Design of Offshore Wind Turbines,” Chapter 2 in Offshore Wind Turbine Foundation Design, DTU Wind Energy, Copenhagen, Denmark, 2015.
7. Alamy, a Transition Piece, a Base for a Wind Turbine at the Walney Offshore Wind Farm, Irish Sea, UK, https://www.alamy.com/a-transition-piece-a-base-for-a-wind-turbine-at-the-walney-off-shore-wind-farm-irish-sea-uk-image283012538.html, accessed on January 22, 2020.
8. J. K. Wang, “Settlement of Gravity Foundations Under Vertical Loads,” M.S. Thesis, National Cheng Kung University, Tainan, Taiwan, 2012.
9. H. Yu, X. Zeng, F. H. Neff, B. Li, and J. Lian, “Centrifuge Modeling of Offshore Wind Foundations Under Earthquake Loading,” Soil Dynamics and Earthquake Engineering, Vol. 77, pp. 402-415, 2015.
10. S. Malhotra, “Design and Construction Considerations for Offshore Wind Turbine Foundations,” in Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, San Diego, California, USA, June 10-15, 2007.
11. D. Chen, K. Huang, V. Bretel, and L. Hou, “Comparison of Structural Properties Between Monopile and Tripod Offshore Wind-Turbine Support Structures,” Advances in Mechanical Engineering, Vol. 5, Article ID 175684, 2015.
12. IEC 61400-1, International Standard Wind Turbines- Part 1: Design Requirements, Third Edition, International Electrotechnical Commission, Geneva, Switzerland, 2005.
13. IEC 61400-3, International Standard Wind Turbines- Part 3: Design Requirements for Offshore Wind Turbines, First Edition, International Electrotechnical Commission, Geneva, Switzerland, 2009.
14. L. Colone, A. Natarajan, and N. Dimitrov, “Impact of Turbulence Induced Loads and Wave Kinematic Models on Fatigue Reliability Estimates of Offshore Wind Turbine Monopoles,” Ocean Engineering, Vol. 155, pp. 295-309, 2018.
15. IEC 61400-24, Wind Energy Generation Systems - Part 24: Lightening Protection, Second Edition, International Electrotechnical Commission, Geneva, Switzerland, 2019.
16. S. Bisoi and S. Haldar, “Dynamic Analysis of Offshore Wind Turbine in Clay Considering Soil–Monopile–Tower Interaction,” Soil Dynamics and Earthquake Engineering, Vol. 63, pp. 19-35, 2014.
17. API RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms-Working Stress Design, Twenty-First Edition, American Petroleum Institute, Washington, D.C., USA, 2010.
18. M. H. Chan, C. Y. Lin, J. H. Lin, T. L. Chu, and C. C. Huang, “A Study on API Standard Strength Check for Local Jacket Type Support Structure of 5 MW Offshore Reference Wind Turbine,” in Proceeding of Conference on Taiwan Wind Energy Association 2015, Taipei, Taiwan, December 8, 2015.
19. S. Jung, S. R. Kim, A. Patil, and L. C. Hung, “Effect of Monopile Foundation Modeling on the Structural Response of a 5-MW Offshore Wind Turbine Tower,” Ocean Engineering, Vol. 109, pp. 479-488, 2015.
20. R. Rezaei, P. Fromme, and P. Duffour, “Fatigue Life Sensitivity of Monopile-Supported Offshore Wind Turbines to Damping,” Renewable Energy, Vol. 123, pp. 450-459, 2018.
21. L. Ziegler, S. Schafhirt, M. Scheu, and M. Muskulus, “Effect of Load Sequence and Weather Seasonality on Fatigue Crack Growth for Monopile-Based Offshore Wind Turbines,” Energy Procedia, Vol. 94, pp. 115-123, 2016.
22. P. Passon, K. Branner, S. E. Larsen, and J. Hvenekær Rasmussen, “Aerodynamic Damping and Hydrodynamic Drag Damping for OWT,” Chapter 4 in Offshore Wind Turbine Foundation Design, DTU Wind Energy, Copenhagen, Denmark, 2015.
23. J. Velarde and E. E. Banchynski, “Design and Fatigue Analysis of Monopile Foundation to Support the DTU 10 MW Offshore Wind Turbine,” Energy Procedia, Vol. 137, pp. 3-13, 2017.
24. P. Passon, “Damage Equivalent Wind-Wave Correlations on Basis of Damage Contour Lines for the Fatigue Design of Offshore Wind Turbines,” Renewable Energy, Vol. 81, pp. 723-736, 2015.
25. R. Biswal and A. Mehmanparast, “Fatigue Damage Analysis of Offshore Wind Turbine Monopile Weldments,” Procedia Structural Integrity, Vol. 17, pp. 643-650, 2019.
26. J. H. Horn, J. R. Krokstad, and J. Amdahl, “Hydro-Elastic Contributions to Fatigue Damage on a Large Monopile,” Energy Procedia, Vol. 94, pp. 102-114, 2016.
27. ASTM Standard E1049-85, Standard Practices for Cycle Counting in Fatigue Analysis, ASTM International, West Conshohocken, PA, USA, 2017.
28. N. E. Dowling, “Fatigue of Materials: Introduction and Stress-Based Approach,” Chapter 9 in Mechanical Behavior of Materials Engineering Method for Deformation, Fracture, and Fatigue, Pearson, London, England, 2013.
29. DNVGL-RP-C203, Recommended Practice Fatigue Design of Offshore Steel Structures, Det Norske Veritas Germanischer Lloyd, Akershus, Norway, April 2016.
30. P. Passon and K. Branner, “Load Calculation Methods for Offshore Wind Turbine Foundations,” Ships and Offshore Structures, Vol. 9, pp. 443-449, 2014.
31. P. Passon, K. Branner, S. E. Larsen, and J. Hvenekær Rasmussen, “Load Calculation Approaches,” Chapter 3 in Offshore Wind Turbine Foundation Design, DTU Wind Energy, Copenhagen, Denmark, 2015.
32. J. Jonkman and W. Musial, “Monopile with Rigid Foundation Modeling of Phase I,” Chapter 2 in Offshore Code Comparison Collaboration (OC3) for IEA Task 23 Offshore Wind Technology and Deployment, National Renewable Energy Laboratory, Golden, Colorado, USA, 2010.
33. DNVGL-ST-0437, Loads and Site Conditions for Wind Turbines, Det Norske Veritas Germanischer Lloyd, Akershus, Norway, November 2016.
34. Wind Towers Welding Consumables in Industry, Tien Tai Electrode, Taoyuan, Taiwan, 2019.
35. P. Wang, M. Zhao, X. Du, J. Liu, and G. Xu, “Wind, Wave, and Earthquake Responses of Offshore Wind Turbine on Monopile Foundation in Clay,” Soil Dynamics and Earthquake Engineering, Vol. 153, pp. 47-57, 2018.
36. A. Kyte and A. Tørum, “Wave Forces on Vertical Cylinders upon Shoals,” Coastal Engineering, Vol. 27, pp. 263-286, 1996.
連結至畢業學校之論文網頁點我開啟連結
註: 此連結為研究生畢業學校所提供,不一定有電子全文可供下載,若連結有誤,請點選上方之〝勘誤回報〞功能,我們會盡快修正,謝謝!
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
無相關論文
 
無相關期刊
 
無相關點閱論文
 
系統版面圖檔 系統版面圖檔