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span, so that each of the two parts was close to the minimum length practical. The other was to locate the joint in the vicinity of 60 to 70 m, near the limit of current transportation feasibility. In every case, the design bending loads would decrease with increasing spanwise position, but the inherent structural efficiency of the connection (due to cross-sectional shape) would decrease as well. There would be numerous parameters involved in the optimization of spanwise joint location, and the most cost-effective solution might depend on the blade length specific distribution of bending load, structural shape of the blade, and intended shipping methods and route. A complete parametric evaluation of these options was beyond the scope of the current study, and the near mid-span option was selected for the analyses. It should be noted that the difference between these two fundamental approaches is most significant for the 75 m blade and diminishes for larger blades as the mid-span length of the 115 m blades approaches that of current large commercial blades. The locations of joints for modular blades are shown schematically in Figure 6-1 through Figure 6-3. Major dimensions for the subcomponents are given in Table 6-1, where “part 1” and “part 2” are the inboard and outboard portions, respectively, for the spanwise joint and “part 3” is the chord extension, or “root cuff.”

Chord (m)

15

10

5

0 0

10

20

30

40

50

60

70

80

Rotor Radius (m) Figure 6-1 Spanwise joint location for 75 m blade

DNV GL – Document No.: 10080081-HOU-R-01, Issue: C, Status: FINAL www.dnvgl.com

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Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

Supersized wind turbine blade study  

R&D pathways for supersized wind turbine bladesSupersized wind turbine blade studyLawrence Berkeley National LaboratoryDocument Number: 1008...

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