Efficient wind turbine blades, wind turbine blade structures, and associated systems and methods of manufacture, assembly and use
Wind turbine systems and methods are disclosed herein. A representative system includes a wind turbine blade having an inner region that has an internal load-bearing truss structure, and an outer region that has an internal, non-truss, load-bearing structure. In particular embodiments, the truss structure can include a triangular arrangement of spars, and/or can include truss attachment members that connect components of the truss without the use of holes in the spars. Spars can be produced from a plurality of pultruded composite members laminated together in longitudinally extending portions. The longitudinally extending portions can be connected at joints that interleave projections and recesses of each of the spar portions. The blades can include fan-shaped transitions at a hub attachment portion, formed by laminated layers and/or a combination of laminated layers and transition plates.
1. A wind turbine system, comprising:
a wind turbine blade including:
a plurality of longitudinally extending spars;
a plurality of longitudinally spaced-apart ribs, with individual ribs attached to the longitudinally extending spars;
a plurality of truss attachment members, with individual truss attachment members connected to a spar without the use of a hole in the spar; and
a plurality of truss members, with individual truss members connected between corresponding pairs of truss attachment member to form a three-dimensional truss structure, with at least one truss member extending diagonally and chordwise, wherein the at least one truss member is in tension.
2. The system of claim 1 wherein:
the spars are formed from a composite material, and wherein the truss attachment members include a spar attachment portion and a truss attachment portion, the spar attachment portion extending circumferentially around a spar and clamped to the spar, the truss attachment portion including a flange extending away from the spar and having a first attachment hole; and
at least one of the truss members includes a second attachment hole; and wherein the system further comprises:
a fastener extending through the first and second attachment holes but not into the spar.
3. The system of claim 2 wherein the truss member has a slot in which the flange of the truss attachment member is received.
4. The system of claim 1 wherein an individual truss attachment member is attached to a spar, and wherein the truss attachment member is formed from a metal and the spar is formed from a composite material.
5. The system of claim 1 wherein an individual truss attachment member is attached to a spar, and wherein both the truss attachment member and the spar are formed from a composite material.
6. The system of claim 5 wherein the spar and the truss attachment member are adhesively bonded.
7. The system of claim 5 wherein the spar and the truss attachment member are co-cured.
8. The system of claim 1 wherein the truss attachment member includes a first component extending circumferentially around a first portion of the spar, a second component extending circumferentially around a second portion of the spar, and at least one fastener connecting the first and second components and clamping the spar between the first and second components.
9. The system of claim 8 wherein the fastener is positioned to both clamp the spar between the first and second components and attach one of the truss members to the truss attachment member.
10. The system of claim 1 wherein:
the spars are formed from a composite material, and wherein the truss attachment members include a first component extending circumferentially around a first portion of the spar and a second component extending circumferentially around a second, complementary portion of the spar, the first component having two first flanges, one extending outwardly from the spar in a first direction, and the other extending outwardly from the spar in a second direction different than the first direction, the second component having two second flanges, one extending outwardly from the spar in the first direction and positioned surface-to-surface against one of the first flanges of the first component, and the other of the second flanges extending outwardly in the second direction and positioned surface-to-surface against the other first flange of the first component, each of the first flanges having a first fastener opening, each of the second flanges having a second fastener opening aligned with a corresponding one of the first fastener openings;
a first truss member having a first slot in which the first flanges are received;
a second truss member having a second slot in which the second flanges are received;
a first fastener passing through the first truss member, one of the first fastener openings, and the corresponding aligned second fastener opening to secure the first truss member to the truss attachment member and clamp the first and second components around the spar; and
a second fastener passing through the second truss member, the other of the first fastener openings, and the corresponding aligned second fastener opening to secure the second truss member to the truss attachment member and clamp the first and second components around the spar; wherein
neither the first nor the second fasteners pass into the spar.
11. The system of claim 1 wherein the truss attachment member is attached to one of the individual spars, and extends around only a portion of the spar.
12. The system of claim 1 wherein the truss attachment member is adhesively attached to one of the individual spars.
13. A method for making a wind turbine blade, comprising:
positioning a plurality of ribs to be longitudinally spaced-apart from each other, the ribs including a first rib and a second rib;
positioning first and second longitudinally extending spars proximate to the ribs;
connecting a first truss attachment member to the first spar without the use of a hole in the first spar;
connecting a second truss attachment member to the second spar without the use of a hole in the second spar; and
connecting a truss member between the first and second truss attachment members, the truss member being one of a plurality of truss members forming a three-dimensional truss structure with at least one truss member extending diagonally and chordwise, wherein the at least one truss member is in tension.
14. The method of claim 13 wherein the first truss attachment member includes a first component and a second component and wherein connecting the first truss attachment member includes clamping the first and second components around the first spar.
15. The method of claim 13 wherein the truss member is a first truss member and wherein the first truss attachment member includes a first component and a second component, the first component having two first flanges, one extending outwardly from the spar in first direction, and the other extending outwardly from the spar in a second direction different than the first direction, the second component having a two second flanges, one extending outwardly from the spar in the first direction and the other of the second flanges extending outwardly from the spar in the second direction, and wherein connecting the first truss attachment member includes:
positioning the first component to extend around a first circumferential portion of the first spar;
positioning the second component to extend around a second circumferential portion of the first spar;
placing one of the first flanges to face toward one of the second flanges to form a first flange pair;
placing the other of the first flanges to face toward the other of the second flanges to form a second flange pair;
receiving the first flange pair in a slot of the first truss member;
receiving the second flange pair in a slot of a second truss member;
both clamping the first and second components around the spar and attaching the first truss member to the first truss attachment member by passing a first fastener through the first truss member and the first flange pair; and
both clamping the first and second components around the spar and attaching the second truss member to the first truss attachment member by passing a second fastener through the second truss member and the second flange pair.
16. The method of claim 13 wherein connecting the first truss attachment member includes connecting the first truss attachment member to the first spar, and wherein connecting the second truss attachment member includes connecting the second truss attachment member to the second spar, and wherein the method further comprises connecting the first rib to the truss member.
17. The method of claim 16 wherein connecting the first rib to the truss member includes connecting the first rib to the truss member with an adhesive.
18. The method of claim 16 wherein the first rib includes a web and a flange, and wherein connecting the first rib to the truss member includes connecting the web of the first rib to the truss member.
19. The method of claim 13 wherein connecting the first truss attachment member includes adhesively bonding the first truss attachment member to the first spar.
20. The method of claim 13 wherein the first truss attachment member and the first spar are formed from composite materials, and wherein connecting the first truss attachment member includes co-curing the first truss attachment member and the first spar.