COMPOSITE RODS FOR STABILIZATION OF COMPOSITE LAMINATES
Structurally enhanced preformed layers of multiple rigid unidirectional rods are constructed and arranged for use in fabricating load-bearing support structures and reinforcements in a variety of composite components, e.g. wind turbine blades. Individual preform layers include multiple elongate unidirectional strength elements or rods arranged in a single layer along a longitudinal axis of the preform layer. Individual rods include aligned unidirectional structural fibers embedded within a matrix resin such that the rods have a substantially uniform distribution of fibers and high degree of fiber collimation. The relative straightness of the fibers and fiber collimation provide rods and the preform layers with high rigidity and significant compression strength. A plurality of rods are loosely attached, e.g. knitted, together with a coupling that allows for each rod to be axially displaced. e.g. slideable, relative to another rod.
1 . (canceled)
2 . A method of forming a composite structural element for a wind turbine comprising:
forming at least one preform layer by:
providing multiple elongate rods arranged longitudinally and aligned relative to one another in a single layer,
disposing each rod adjacent to and spaced from at least one adjacent rod;
each elongate rod including multiple unidirectional, substantially straight collimated structural fibers bonded in a solidified matrix resin so that each rod is rigid and defines a finished geometry;
providing a coupling, the coupling connecting at least a first rod to an adjacent rod, the coupling configured as a cell structure having a plurality of cross beams oriented perpendicular to the elongate rods, wherein:
the plurality of rods remain in a single plane, and
the coupling remains positioned in a fixed relationship relative to
the rods, and
disposing the composite structural element in a wind turbine blade mold.
3 . The method of claim 1 , further comprising providing multiple preform layers, and stacking a first preform layer on top of a second preform layer.
4 . The method of claim 2 , further comprising dispensing a resin between stacked preform layers and individual rods.
5 . The method of claim 1 , wherein at least one rod is configured with a planar construction.
6 . The method of claim 1 , wherein at least one rod is configured with a uniform diameter.
7 . The method of claim 1 , wherein the spacing between two rods remains constant.
8 . The method of claim 1 , wherein coupling is adhesive free.
9 . The method of claim 1 , wherein at least one rod is free to move with respect to the coupling cell structure.
10 . The method of claim 8 , wherein the movement includes sliding longitudinally with respect to the coupling cell.
11 . The method of claim 1 , wherein at least one cross beam of the coupling is disposed above the rod.
12 . The method of claim 1 , wherein at least one cross beam of the coupling is disposed below the rod.
13 . The method of claim 1 , wherein at least one rod is captured in a knitted architecture of lightweight textile yarns.
14 . The method of claim 12 , wherein the lightweight textile yarns comprises polyester.
15 . The method of claim 12 , wherein the lightweight textile yearns comprises aramid.
16 . The method of claim 12 , wherein the lightweight textile yarns comprises carbon.
17 . The method of claim 12 , wherein the lightweight textile yarns comprises acrylic.
18 . The method of claim 1 , wherein the at least one rod is spaced from an adjacent rod at an angle of less than 2 degrees.
19 . The method of claim 1 , wherein an edge of the structural element is completely encircled by a knit member.