33 2 Vol.33 No.2 2016 2 Feb. 2016 ENGINEERING MECHANICS 209 1000-4750(2016)02-0209-07 1,2 1 (1. 410082 2. ( ) 410082) 16 m ABAQUS 4 4 TK83 A doi: 10.6052/j.issn.1000-4750.2014.06.0548 NUMERICAL SIMULATION ON A JOINT SEGMENT OF A PRESTRESSED PREFABRICATED SECTIONAL WIND TURBINE BLADE MODEL XU Bin 1,2, HAN Ji-long 1 (1. College of Civil Engineering, Hunan University, Changsha, Hunan 410082, China; 2. Hunan Provincial Key Laboratory of Damage Diagnosis for Engineering Structures (Hunan University), Changsha, Hunan 410082, China) Abstract: As high-power wind turbines develop, the length of the turbine blades tends to increase, and thus the difficulties, risk, and cost involved in transportation increase, especially for those wind farms located in mountainous areas. Dividing a traditional blade into several prefabricated segments and assembling them on-site is an efficient solution to overcome the above problems. In this study, a new prefabricated sectional wind turbine blade assembled by connecting the sectional blades with prestressed high-strength bolts is proposed and a stress analysis on the joint segment of the prefabricated blade model is carried out using a finite element method. The joint segment of a typical wind turbine blade is modeled with ABAQUS. The stress distribution of the joint segment is analyzed under four different design load cases in both flatwise and edgewise directions. Numerical simulation results show that the stress of the wind turbine blade and prestressed bolts under the four design load cases are all within the materials acceptable stress range. In conclusion, the proposed prefabricated sectional blade using prestressed bolts is proven feasible and can be an alternative approach of traditional wind turbine blades. Key words: prefabricated sectional wind turbine blade; finite element method; prestressed bolt connection; stress analysis; glass fiber reinforced plastic 2014-06-242015-01-30 (2013FJ2010) (1972 )(E-mail: binxu@hnu.edu.cn). (1988 ) (E-mail: hanjilong23@qq.com).
210 [1 2] 40 m Vestas V112-3.0 MW 55 m [3] 6.0 m/s Hahn [4] [5 7] 2 MW 46.5 m 16 m 4 1 1 16 m 2 2(a) 2(b) (a) (b) 2 Fig.2 Prefabricated sectional blade and cross section 3 4 1 ~7 13 ~20 26 ~32 36 mm 8 ~12 21 ~25 39 mm 33 14 mm 1 2 1 2 1 2 5 1 Fig.1 Whole prefabricated wind turbine blades 3 Fig.3 Connection scheme of sectional blade
211 4 Fig.4 Distribution of bolts in section 5 Fig.5 Connection of high strength bolt 2 2.1 ABAQUS [8 9] Auto CAD ABAQUS 6 (b) 8 Fig.8 Model of connection section ABAQUS ABAQUS 7 8 40 mm 75 mm 40 mm 70 mm 500 mm 590 mm 1 2 ABAQUS 9~ 11 12 9 Fig.9 Model of screw 10 1 Fig.10 Model of connector 1 11 2 Fig.11 Model of connector 2 6 Fig.6 Model of general section 12 Fig.12 Whole model of joint segment 7 Fig.7 Model of transition section (a) 2.2 1 10.9 2
212 1 Table 1 Performance parameters of glass fiber reinforced plastic 2 x /MPa 99.2 E x /GPa 13 G xy /GPa 4.64 cx /MPa 137.52 x /MPa 894.8 E x /GPa 41 y /MPa 61.33 E y /GPa 14.67 Т xy /MPa 51.1 G xy /GPa 5.3 cx /MPa 624.2 cy /MPa 181.5 x /MPa 312.56 E x /GPa 18.02 y /MPa 177.29 E y /GPa 14.45 Т xy /MPa 263.34 G xy /GPa 9.74 cx /MPa 288.52 x /MPa 603.14 E x /GPa 28.35 y /MPa 145.27 E y /GPa 14.58 Т xy /MPa 183.79 G xy /GPa 7.6 cx /MPa 533.31 Table 2 Performance parameter of high-strength bolt /MPa /MPa /GPa 900 1040 206 0.3 2.3 [9] 3 13 2.4 2.4.1 3 Table 3 Type and number of the elements C3D8R 418 C3D8R 1691 C3D10 11487 C3D10 38300 C3D10 6134 C3D10 332819 1 C3D8R 18552 2 C3D8R 11492 C3D8R 65614 13 Fig.13 The FEM mesh of the joint segment P [10] 0.9 0.9 0.9 P Aefu (1) 1.2 A e f u 10.9 2 fu 1040 N / mm 4 4 Table 4 Prestress of the connection bolts /mm A e /mm 2 f u /(N/mm 2 ) P/kN 14 115 1040 72.657 36 817 1040 516.181 39 976 1040 616.637 2.4.2 16 m 5 IEC 61400-1 [11] 5 Table 5 Load case at the sectional division / (kn m) / (kn m) /kn /kn 3108.6 218.1 227.0 6.77 1933.7 937.3 163.9 53.2 1598.6 2068.5 127.8 152.7 430.6 1160.9 43.4 102.5
213 2.4.3 [12] 3 4 [13] Mises 1 2 14 1 14 S, S33 ( : 75%) 1.119 10 2 8.148 10 1 5.107 10 1 2.065 10 1 9.760 10 0 4.017 10 1 7.059 10 1 1.010 10 2 1.314 10 2 10 2 z 1.922 10 2 2.227 10 2 2.531 10 2 y x 14 z Fig.14 z-direction stress of connection section for the prestressed load 15~ 23 x y z x y z 1 2 3 z Mises 24 15 x Fig.15 x-direction stress of general section 16 y Fig.16 y-direction stress of general section 17 z Fig.17 z-direction stress of general section S, S11 ( : 75%) 7.241 10 1 6.090 10 1 4.938 10 1 3.787 10 1 2.635 10 1 1.484 10 1 3.322 10 0 8.193 10 0 1.971 10 1 10 1 4.274 10 1 5.425 10 1 6.577 10 1 18 x Fig.18 x-direction stress of transition section 19 y Fig.19 y-direction stress of transition section 20 z Fig.20 z-direction stress of transition section
214 6 /MPa Table 6 Results of the max flapwise bending moment 21 x Fig.21 x-direction stress of connection section 22 y Fig.22 y-direction stress of connection section 23 z Fig.23 z-direction stress of connection section zmax zmin 116.3 106.2 39.22 33.6 59.05 52.48 67.76 69.97 111.2 94.78 40.55 50.16 201.3 355.6 678.2 7 /MPa Table 7 Results of the min flapwise bending moment zmax zmin 73.57 76.62 23.98 25.25 39.07 38.03 44.56 46.28 69.49 69.55 26.59 42.17 166.3 333.4 678.4 8 /MPa Table 8 Results of the max edgewise bending moment zmax zmin 24 Mises Fig.24 Mises stress distribution of prestressed bolts 3 4 6~ 9 4 4 (1) 64.15 75.41 20.35 24.9 34.6 38.52 29.28 52.68 60.65 67.51 23.34 40.83 159.2 328.1 678.1 9 /MPa Table 9 Results of the min edgewise bending moment zmax zmin 33.81 12.82 11.59 4.908 17.73 28.71 20.03 12.32 31.61 21.61 13.59 29.97 97.89 265 678.8 (2)
215 (3) (4) [1] Yu X, Qu H. Wind power in China opportunity goes with challenge [J]. Renewable and Sustainable Energy Reviews, 2010, 14(8): 2232 2237. [2] Fried L, Sawyer S, Shukla S, et al. Global wind report- Annual market update [J]. Global Wind Energy Council, 2012, 10(2): 30 33. [3] Hopwood D. Generation innovation [J]. Renewable Energy Focus, 2011, 12(2): 36 41. [4] Hahn F, Kensche C W, Paynter R J H, et al. Design, fatigue test and NDE of a sectional wind turbine rotor blade [J]. Journal of Thermoplastic Composite Materials, 2002, 15(3): 267 277. [5],,. [J]., 2004, 21(6): 118 123. Li Deyuan, Ye Zhiquan, Chen Yan, Bao Nengsheng. Load spectrum and fatigue life analysis of the blade of horizontal axis wind turbine [J]. Engineering Mechanics, 2004, 21(6): 118 123. (in Chinese) [6],,. [J]., 2013, 30(2): 477 480. Cai Xin, Zhu Jie, Pan Pan. The best shape design of horizontal axis wind turbine blade [J]. Engineering Mechanics, 2013, 30(2): 477 480. (in Chinese) [7],. [J]., 2012, 30(2): 406 412. Zhang Xu, Xing Jingzhong. Simulation on the effect of local damage of blade on static and dynamic characteristics for large horizontal axis wind turbine [J]. Engineering Mechanics, 2012, 30(2): 406 412. (in Chinese) [8] Bechly M E, Clausen P D. Structural design of a composite wind turbine blade using finite element analysis [J]. Computers & Structures, 1997, 63(3): 639 646. [9] Hibbitt D, Karlsson B, Sorensen P. ABAQUS analysis user s manual [J]. Pawtucket, USA, 2004, 11(3): 95 99. [10]. [M]. :, 2004: 95 99. Zhang Yaochun. Steel structure design principles [M]. Beijing: Higher Education Press, 2004: 95 99. (in Chinese) [11] EN 61400-1-2010, Wind turbines - Part 1: Design requirements (IEC 61400-1) [S]. International Electrotechnical Commission, 2010. [12],. [J]., 2009, 26(9): 50 53. Fu Cheng, Wang Yanrong. Research of 3D finite element modelling on wind wheel blade of wind power generator [J]. Journal of Machine Design, 2009, 26(9): 50 53. (in Chinese) [13]. [M]. :, 2012: 50 61. Wang Yaoxian. Mechanics and structural design of composite materials [M]. Shanghai: East China University of Science and Technology Press, 2012: 50 61. (in Chinese)