﻿ 冰区海上风机的动力响应及疲劳分析
 舰船科学技术  2018, Vol. 40 Issue (1): 81-85 PDF

Dynamic response and fatigue analysis of offshore wind turbine in ice region
ZHANG Yi, MA Yong-liang, QU Xian-qiang, HAN Chao-shuai
College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Key words: wind load     ice load     offshore wind turbine     dynamic response     fatigue damage
0 引　言

1 风载荷计算

1.1 平均风速的计算

 $V\left( z \right) = V\left( {{z_r}} \right){\left( {z/{z_r}} \right)^\alpha }\text{，}$ (1)

1.2 脉动风速的模拟

1.2.1 Kaimal风速谱

 ${S_K}\left( f \right) = \frac{{4\sigma _K^2{L_K}/{V_{hub}}}}{{{{\left( {1 + 6f{L_K}/{V_{hub}}} \right)}^{5/3}}}}\text{。}$ (2)

 ${L_K} = \left\{ \begin{array}{l}8.10{\Lambda _U}, \;\;\;K = u\text{；}\\2.70{\Lambda _U}, \;\;\;K = v\text{；}\\0.66{\Lambda _U}, \;\;\;K = w\text{。}\end{array} \right.$ (3)

 ${\Lambda _U} = 0.7 \cdot \min (60,{Z_{hub}})\text{。}$ (4)

 ${\sigma _v} = 0.8{\sigma _u}\text{，}$ (5)
 ${\sigma _w} = 10.5{\sigma _u}\text{。}$ (6)
1.2.2 脉动风速场的相干性

 图 1 脉动风速场网格划分 Fig. 1 Grids of fluctuating wind speed field

 $Coh\left( {r,f} \right) = \exp \left[ { - 12\sqrt {{{\left( {\frac{{fr}}{{{V_{hub}}}}} \right)}^2} + {{\left( {0.12\frac{r}{{{L_c}}}} \right)}^2}} } \right]\text{。}$ (7)

1.2.3 Sandia法

1.3 气动载荷计算

2 冰载荷计算

Kӓrnӓ认为总的冰力Ftotalt）应该是平均冰力分量 $\overline F$ 与脉动冰力分量Ft）之和 ，即

 ${F_{total}}(t) = \overline F + F(t)\text{，}$ (8)

 ${F_{\max }} = \overline F + k\sigma \text{，}$ (9)
 $I = \frac{\sigma }{{\overline F }}\text{。}$ (10)

 $\sigma = \frac{I}{{1 + kI}}{F_{\max }}\text{，}$ (11)
 $\overline F = \frac{{{F_{\max }}}}{{1 + kI}}\text{。}$ (12)

 ${F_{\max }} = {C_R}\left( {\frac{h}{{{h_1}}}} \right){\left( {\frac{w}{h}} \right)^m}hw\text{，}$ (13)

 $n = \left\{ \begin{array}{l} - 0.5 + h/5\;\text{，}\;\;h < 1.0\;m\text{，}\\{\rm{ - }}0.3\;\;\;\;\text{，}\;\;\;\;\;\;\;\;h > 1.0\;m\text{。}\end{array} \right.$ (14)

 $\tilde S\left( f \right) = \frac{{fS\left( f \right)}}{{{\sigma ^2}}}\text{，}$ (15)
 $\tilde S\left( f \right) = \frac{{af}}{{1 + {k_s}{a^{1.5}}{f^2}}}\text{。}$ (16)

3 计算实例 3.1 风机模型

 图 2 风机结构示意图 Fig. 2 Structural sketch of offshore wind turbine

 图 3 塔顶坐标系定义 Fig. 3 The definition of coordinate system at the top of tower
3.2 载荷分析

 图 4 轮毂处纵向风速 Fig. 4 Longitudinal wind speed at hub

 图 5 塔筒顶端载荷 Fig. 5 Wind load at the top of tower

 图 6 冰载荷时间历程 Fig. 6 Ice load time history

3.3 风机动力响应分析

 图 7 泥面处坐标系定义 Fig. 7 The definition of coordinate system at the mudline

 图 8 塔筒顶端纵向位移 Fig. 8 Longitudinal displacement at hub

 图 9 泥面处支反力Fx Fig. 9 Bearing force at the mudline

 图 10 泥面处弯矩 Fig. 10 Bending moment at the mudline
3.4 疲劳损伤评估

 图 11 泥面处节点应力时间历程 Fig. 11 Node stress time history at the mudline

4 结　语

1）风载荷作用下塔筒顶端的纵向位移要远远大于冰载荷作用。

2）风载荷与冰载荷单独作用下，泥面处的支反力相当。冰载荷作用下的泥面处的弯矩要要小于风载荷作用。当风冰载荷联合作用时，泥面处的支反力与弯矩均大于单一载荷的作用。

3）冰载荷对风机造成的疲劳损伤值要小于风载荷。DNV方法叠加计算得到的损伤值要大于风冰联合作用计算得到的结果，偏于保守。因此，推荐使用DNV方法。

 [1] T. A numerical model for for dynamic ice-structure interaction[J]. Computers and Structures, 1999, 72 : 645–668. DOI: 10.1016/S0045-7949(98)00337-X [2] International Electrical Commission. IEC 61400–3, Wind turbines–Part 3: Design requirements for offshore wind turbines [S]. London, 2001. [3] 王翎羽, 徐继祖. 冰与结构动力相互作用的理论分析模型[J]. 海洋学报, 1993, 15 (3): 140–146. [4] Q. Dynamic ice forces of slender vertical structures due to ice crushing[J]. Cold Regions Science and Technology, 2009, 56 : 77–83. DOI: 10.1016/j.coldregions.2008.11.008 [5] WANG Qi. Ice-induced vibrations under continuous brittle crushing for an offshore wind turbine[D]. Delft: Technische Universiteit Delft, 2015. [6] WELLS E M. An assessment of surface ice sheet loads and their effects on an offshore wind turbine structure[D]. Toledo: The University of Toledo, 2012. [7] 方华灿, 徐发彦, 陈国明. 冰区海上平台管节点疲劳寿命计算的新方法[J]. 中国海洋平台, 1997, 12 (6): 259–263. [8] 黄焱, 马玉贤, 罗金平, 等. 渤海海域单柱三桩式海上风电结构冰激振动分析[J]. 海洋工程, 2016, 34 (5): 1–10. [9] International Electrical Commission. IEC 61400-1, Wind turbines–Part 1.: Wind turbines[S]. London, 2005. [10] VERITAS D N. DNV-RP-C205, Environmental conditions and environmental loads[S]. Oslo, 2010. [11] VEERS P S. Three-dimensional wind simulation[R]. NM: Sandia National Laboratories, 1988. [12] KUMH M. Dynamic and design optimization of offshore wind energy conversion system[D]. Delft: Technische Universiteit Delft, 2001. [13] International Organization for Standardization. ISO 19906, Petroleum and natural gas industries – Arctic offshore structures[S]. Switzerland, 2012. [14] 张增海, 曹越男, 赵伟. 渤海湾海域风况特性分析与海-陆风速对比分析[J]. 海洋预报, 2011, 28 (6): 33–39. DOI: 10.11737/j.issn.1003-0239.2011.06.006 [15] 中国海洋总公司. Q/Hsn 3000-2002, 中国海海冰条件及应用规定[S]. 北京, 2002. [16] 吴龙涛, 吴辉碇, 李万彪, 等. 渤海冰漂移对海面风场、潮流场的响应[J]. 海洋学报, 2005, 27 (5): 15–21. [17] HUANG W, MOAN T. Fatigue under combined high and low frequency loads[C]//25th International Conference on Offshore Mechanics and Arctic Engineering, Hanburg, 2006 [18] TEMPEL V D. Design of support structures for offshore wind turbines[D]. Delft: Technische Universiteit Delft, 2006. [19] Det Norske Veritas. DNV-RP-C203, fatigue design of offshore steel structure[S]. Oslo, 2011. [20] HAN C. A practical method for combination of fatigue damage subjected to low-frequency and high-frequency Gaussian random processes[J]. Applied Ocean Research, 2016, 60 : 47–60. DOI: 10.1016/j.apor.2016.08.007