Shifting layup method for structural composite components with complex surface geometry and non-linear fiber path
Shifting is a method for manipulating unidirectional non-crimp fabrics that allows for a curved fiber path along with compound surface geometry. The bases for shifting is understanding unidirectional (UD) non-crimp-fabrics (NCFs) as a semi-flexible prismatic linkage and planning manipulations such that the array of linkages can conform to the surface geometry and path plan within allowable manufacturing tolerances. This has applications in structural composite components such as the current trailing edge prefabricated unidirectional components for wind turbine blades, and for future wind turbine blade designs including a curve-linear spar cap.
1. A method of fabricating a composite fabric comprising:
providing a continuous supply of composite non-crimp material;
feeding the continuous supply of composite non-crimp material through at least one pair of rollers,
the rollers having an arcuate outer surface configured to engage the continuous supply of composite material;
performing a shifting operation on the continuous supply of composite material, the shifting operation performed continuously and synchronized with the feeding step; and
depositing the shifted composite non-crimp material into a mold for a wind blade;
wherein the rollers have a parabolic shape.
2. The method of claim 1 , wherein the shifting operation forms a curve-linear spar cap.
3. The method of claim 1 , wherein the continuous shifting is achieved by feeding a laminate through two in-line pairs of rollers.
4. The method of claim 1 , wherein the external surfaces of the rollers has a curved or arcuate mating surface.
5. The method of claim 1 , wherein an outfeed roller is powered.
6. The method of claim 1 , wherein an infeed roller is torque controlled to maintain tension in the fabric.
7. The method of claim 1 , wherein the pair of rollers are synchronized to rotate at the same speed and direction and duration.
8. The method of claim 1 , wherein each roller is connected to a frame on a linear axis drive, which is perpendicular to the feed direction on the plane of the supply material fiber.
9. The method of claim 1 , wherein the number of shifts is determined by amount of degradation of supply material structure.
10. The method of claim 1 , wherein a pair of clamps open and close in tandem with the rollers.
11. The method of claim 1 , wherein a shifting head is configured to shift fabrics of up to approximately 280 mm in width.
12. A method of fabricating a composite fabric comprising:
providing a continuous supply of composite non-crimp material;
feeding the continuous supply of composite non-crimp material through at least one pair of rollers,
the rollers having an arcuate outer surface configured to engage the continuous supply of composite material;
performing a shifting operation on the continuous supply of composite material, the shifting operation performed continuously and synchronized with the feeding step; and
depositing the shifted composite non-crimp material into a mold for a wind blade;
wherein the rollers have a bulbous shape.
13. The method of claim 1 , wherein the shifting operation forms a curve-linear spar cap.
14. The method of claim 1 , wherein an outfeed roller is powered.
15. The method of claim 1 , wherein an infeed roller is torque controlled to maintain tension in the fabric.
16. The method of claim 1 , wherein each roller is connected to a frame on a linear axis drive, which is perpendicular to the feed direction on the plane of the supply material fiber.
17. The method of claim 1 , wherein a pair of clamps open and close in tandem with the rollers.