Transition zone in wind turbine blade

• US 20050180854A1
• Filed: 03/19/2003
• Published: 08/18/2005
• Est. Priority Date: 03/19/2002
• Status: Active Grant

• Current Assignee: LM Glasfiber A/S (GE Aerospace)
• Original Assignee: LM Glasfiber A/S (GE Aerospace)
• Inventors: Grabau, Peter, Andersen, Lars Fuglsang
• Granted Patent: US 7,364,407 B2
• Time in Patent Office: Days
• US Class Current: 416/241.R
• CPC Class Codes: B29L 2031/085 Wind turbine blades
• CPC Class Codes: F03D 1/065 characterised by their construction elements F03D13/10 takes precedence
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention relates to a wind turbine blade and a transitional shell blank for the manufacture of the shell of a wind turbine blade, the blade or the transitional shell blank being made of fibre-reinforced polymer including a first type of fibres (1, 3, 6) of a first stiffness and a first elongation at breakage, and a second type of fibres (2, 5, 7) of a different stiffness and a different elongation at breakage. According to the invention the two types of fibres are distributed in the polymer matrix. When seen in a sectional view perpendicular to longitudinal direction of the blade or the transitional shell blank, the quantitative ratio of the two types of fibres varies continuously in the longitudinal direction of the blade or of the transition shell blank.

Claims

1. Wind turbine blade of fibre-reinforced polymer including a first type of fibres (1, 3, 6) of a first stiffness and a first elongation at breakage, and a second type of fibres (2, 5, 7) of a different stiffness and different elongation at breakage, characterised in that the two types of fibres are distributed in the polymer matrix and that when seen in a sectional view perpendicular to the longitudinal direction of the blade the quantitative ratio of the two types of fibres varies continuously in the longitudinal direction of the blade.

2. Wind turbine blade according to claim 1, wherein the first type of fibres is glass fibres (1) and the second type of fibres is carbon fibres (2).

3. Wind turbine blade according to claim 1, characterised in that the quantitative ratio increases or decreases continuously from a first level to a second level.

4. Wind turbine blade according to claim 1, characterised in that the quantitative ratio varies continuously in a transition zone of a length less than the length of the blade.

5. Wind turbine blade according to claim 4, characterised in that the transition zone is provided between a first zone (I) and a second zone (II), said zone both having a substantially uniform quantitative ratio between the two types of fibres.

6. Wind turbine blade according to claim 5, wherein the length of the transition zone (II) is between 0.5 and 1 metre.

7. Wind turbine blade according to claim 4, wherein the blade is divided into the transition zone (II) including the blade root and an additional zone including the rest of the blade.

8. Wind turbine blade according to claim 4, wherein the blade is divided into the transition zone (II) including the blade tip and an additional zone including the rest of the blade.

9. Wind turbine blade according to claim 4, characterised in that fibres or fibre bundles of the first type (I) with different lengths extend from a first end of the transition zone (II) and fibres or fibre bundles of the second type (2) extend from the opposite end of the transition zone.

10. Wind turbine blade according to claim 4, characterised in that the transition zone (II) is formed of a laminate of several fibre layers (6, 7), in which each fibre layer has a boundary surface (10) at a position in the longitudinal direction, the fibre layer including fibres of the first type (6) on one side of the boundary surface and fibres of the second type (7) on the other side of the boundary face, the boundary surfaces (10) of each fibre layer being displaced in relation to the other layers in the longitudinal direction of the blade.

11. Wind turbine blade according to claim 10, wherein the boundary surfaces (11) are serrated when seen in a sectional view parallel to the fibre layers (3, 4, 5).

12. Wind turbine blade according to claim 11, wherein the tips (12) of the serrated boundary surfaces (11) are displaced in relation to each other in the transverse direction of the blade.

13. Wind turbine blade according to claim 1, characterised in that the two types of fibres (1, 2, 3, 5, 6, 7) are distributed in strengthening bands extending in the longitudinal direction of the blade, the remaining portions of the blade'"'"'s cross section having a constant content of fibres of the first type (1, 3, 6) and/or of the second type (2, 5, 7).

14. Prefabricated transition shell blank for the manufacture of the shell of a wind turbine blade, said transition shell blank being made of fibre-reinforced polymer including a first type of fibres (1, 3, 6) of a first stiffness and a first elongation at breakage, and a second type of fibres (2, 5, 7) of a different stiffness and a second elongation at breakage, characterised in that the two types of fibres are distributed in the polymer matrix and that when seen in a sectional view perpendicular to the longitudinal direction of the blade the quantitative ratio varies continuously in the longitudinal direction of the transitional shell blank.

15. Prefabricated transitional shell blank according to claim 14, characterised in that it is shaped as a band for reinforcement of the areas of the blade shell forming the pressure and suction sides of the blade and being furthest spaced apart from the centre of the blade cross section.