Rotor blade root assembly for a wind turbine
The present disclosure is directed to a root assembly for a rotor blade of a wind turbine and methods of manufacturing same. The root assembly includes a blade root section having an inner sidewall surface and an outer sidewall surface separated by a radial gap, a plurality of root inserts spaced circumferentially within the radial gap, and a plurality of spacers configured between one or more of the root inserts. Further, each of the root inserts includes at least one bushing surrounded by a pre-cured or pre-consolidated composite material. In addition, the spacers are constructed of a pre-cured or pre-consolidated composite material.
1. A method of manufacturing a root assembly for a rotor blade of a wind turbine, the method comprising:
placing an outer layer of thermoplastic material into a shell mold of a blade root section of the rotor blade to form an outer sidewall surface of the root assembly;
placing a plurality of root inserts atop the outer layer, wherein each of the root inserts includes at least one metal bushing surrounded by a thermoplastic material;
placing an inner layer of thermoplastic material into a shell mold atop the root inserts to form an inner sidewall surface of the root assembly;
heating the metal bushings of the root inserts such that the surrounding thermoplastic material is heated; and
welding the heated thermoplastic material of the root inserts to the inner and outer layers.
2. The method of claim 1 , wherein the plurality of root inserts comprise pultruded root inserts.
3. The method of claim 1 , further comprising placing a bonding agent between the outer and inner sidewall surfaces.
4. The method of claim 3 , wherein the bonding agent comprises chopped fiber mat (CFM), a biaxially-stretched plastic film, or a three-dimensional glass fabric.
5. The method of claim 1 , wherein the thermoplastic material of the inner layer, outer layer, and/or inserts comprises a plurality of fiber materials, wherein the plurality of fiber materials comprise at least one of carbon fibers, carbon rovings, glass fibers, or glass rovings.
6. The method of claim 1 , further comprising placing one or more spacers between at least one pair of inserts of the plurality of inserts.
7. The method of claim 6 , wherein the one or more spacers further comprise a low-density core material.
8. The method of claim 6 , wherein the plurality of root inserts and the one or more spacers comprise side edges such that when the root inserts and spacers are arranged in the root assembly, the side edges align and are substantially flush to form first and second continuous surfaces.
9. The method of claim 6 , wherein the plurality of root inserts and the one or more spacers comprise corresponding cross-sectional shapes, the corresponding cross-sectional shapes comprising one of a square or a rectangle.