Lightweight composite truss wind turbine blade
A lightweight wind turbine blade formed with a truss support structure assembly of composite truss joints including composite spar and cross members attached to and supporting in spaced relation a spine of lightweight rib panels. The rib panels are oriented in parallel spaced relation from one another and individually molded with perimeters defining individual areas of curvature for the finished blade assembly. The truss support structure is covered with a lightweight fiberglass or hardened fabric skin attached to and fitted on respective rib panel edges forming an airfoil structure.
1. A wind turbine blade, comprising:
a wind turbine blade skin having a low pressure surface facing in a first direction and a high pressure surface facing in a second direction opposite the first direction;
a plurality of spaced-apart wind turbine blade rib panels positioned within the skin;
multiple spars extending between neighboring rib panels in a spanwise direction, wherein at least one of the spars is curved in two directions transverse to the spanwise direction; and
multiple cross members extending diagonally between spars, with the ribs, spars and cross members forming a truss structure.
2. The wind turbine blade of claim 1 wherein the at least one spar is curved in a chordwise direction and in a camber direction.
3. The wind turbine blade of claim 1 wherein the at least one spar is one of four spars positioned within the wind turbine blade skin.
4. The wind turbine blade of claim 1 wherein at least one of the spars has a first portion connected to a second portion at a spar joint.
5. The wind turbine blade of claim 1 further, comprising:
a circular mounting ring; and
a transition structure connected between the truss structure and the mounting ring, wherein the spars are attached to the transition structure.
6. A wind turbine blade, comprising:
a wind turbine blade skin;
a plurality of wind turbine blade ribs positioned within the skin;
a plurality of spars extending between neighboring ribs in a spanwise direction, at least one of the spars having a first portion connected to a second portion at a spar joint; and
a plurality of cross members extending diagonally between the spars, with the ribs, spars and cross members forming a truss structure.
7. The wind turbine blade of claim 6 wherein the spar joint includes a splice joint.
8. The wind turbine blade of claim 6 , further comprising a bridging member attached to both the first and second portions of the at least one spar at the spar joint.
9. The wind turbine blade of claim 8 wherein the bridging member is bolted to the first and second portions.
10. The wind turbine blade of claim 6 wherein the first and second portions of the at least one spar are connected with bolts.
11. The wind turbine blade of claim 6 wherein individual cross members are attached to individual spars at truss joints and wherein the spar joint is located between and spaced apart from neighboring truss joints.
12. The wind turbine blade of claim 6 wherein spar joint is located between and spaced apart from neighboring wind turbine ribs.
13. The wind turbine blade of claim 6 wherein an individual rib includes a recess and wherein an individual spar is received in the recess of the rib.
14. The wind turbine blade of claim 13 wherein an outer surface of the individual spar is generally flush with an outer surface of the individual rib.
15. The wind turbine blade of claim 6 wherein the skin includes multiple skin sections carried by the truss structure.
16. The wind turbine blade of claim 6 wherein at least one of the cross members includes a slot and a through-hole that extends generally transverse to the slot, and wherein the cross member is coupled to the rib with a fastener that passes through the through-hole.
17. A wind turbine blade, comprising:
a wind turbine blade skin having a tip region and a root attachment region;
a plurality of wind turbine blade ribs positioned within the skin;
a plurality of spars extending between neighboring ribs in a spanwise direction;
a plurality of cross members extending diagonally between the spars, with the ribs, spars and cross members forming a truss structure;
a generally circular mounting ring; and
a transition structure connected between the truss structure and the mounting ring, wherein the spars are attached to the transition structure.
18. The wind turbine blade of claim 17 wherein the transition structure includes a collar attached to the ring, the collar having reinforced regions projecting away from the ring, and wherein the spars are attached to the hard points.
19. The wind turbine blade of claim 18 wherein the reinforced regions include hard points.
20. The wind turbine blade of claim 17 wherein the plurality of spars includes four spars.
21. The wind turbine blade of claim 17 wherein the mounting ring includes mounting holes positioned to bolt the mounting ring to a wind turbine hub.
22. The wind turbine blade of claim 17 wherein at least part of the transition structure tapers as it extends from away from the spar and towards the mounting ring.
23. The wind turbine blade of claim 22 wherein the tapering part of the transition structure includes a fan-shaped portion that has an increasing circumferential extent as extends away from the spar and toward the mounting ring.