Method of joining blade sections using thermoplastics
A segmented rotor blade for a wind turbine includes a first rotor blade segment, a second rotor blade segment, at least one thermoplastic material, and an internal pressure source. The first rotor blade segment includes a first joint end. The second rotor blade segment includes a second joint end. The first and second joint ends are arranged together in an end-to-end orientation so as to form at least one scarf joint. The at least one thermoplastic material is arranged at each of the first and second joint ends. The first and second joint ends of the first and second rotor blade segments are bonded together via thermoplastic welding of the at least one thermoplastic material. The internal pressure source provides pressure to the scarf joint during the thermoplastic welding. The internal pressure source remains within the rotor blade after thermoplastic welding is complete.
1. A method for joining rotor blade segments of a rotor blade, the method comprising:
positioning an upper core material adjacent to a first inner surface of a first side of the rotor blade at a joint between a first blade segment and a second blade segment of the rotor blade;
positioning a separate, a lower core material adjacent to an opposing, second inner surface of a second side of the rotor blade at the joint between the first blade segment and the second blade segment;
placing at least one inflatable internal bladder between the upper and lower core materials;
arranging a first joint end of the first blade segment with a second joint end of the second blade segment at the joint, each of the first and second joint ends comprising at least one thermoplastic material;
arranging the first and second joints ends in an end-to-end orientation with the at least one thermoplastic material of each of the first and second joint ends contacting each other;
inflating the at least one internal bladder so as to provide a localized internal pressure to the joint of the first and second blade segments from within the rotor blade via the upper and lower core materials; and,
applying heat to the thermoplastic materials at the first and second joint ends so as to join the first and second rotor blade segments.
2. The method of claim 1 , further comprising deflating the internal bladder and leaving the internal bladder within the rotor blade.
3. The method of claim 1 , further comprising wrapping at least one of an outer surface or an inner surface of each of the first and second joint ends with the at least one thermoplastic material.
4. The method of claim 1 , wherein inflating the internal bladder so as to provide pressure at the joint from within the first and second blade segments further comprises applying pressure to the internal bladder of one (1) pounds per square inch (lbs./in.2) to two (2) lbs./in.2.
5. The method of claim 1 , further comprising applying heat to the at least one thermoplastic material at the first and second joint ends via at least one of an external mat or a convection source.
6. A method for joining closed rotor blade segments of a rotor blade, the method comprising:
providing a core material at least partially within at least one of a first blade segment or a second blade segment;
placing an upper internal bladder atop the core material and a lower internal bladder below the core material, the upper internal bladder being adjacent to a first inner surface of the first blade segment and the lower internal bladder being adjacent to a second inner surface of the second blade segment;
arranging a first joint end of the first blade segment with a second joint end of the second blade segment at a joint;
inflating the upper and lower internal bladders to provide an internal pressure at the joint from within the first and second blade segments;
joining the first and second joint ends while the joint is under internal pressure so as to join the first and second rotor blade segments; and,
deflating the upper and lower internal bladders within the first and second blade segments, the upper and lower internal bladders remaining in place after the first and second joint ends are joined.
7. The method of claim 6 , further comprising encapsulating at least one of a first joint end of a first rotor blade segment or a second joint end of a second rotor blade segment in at least one thermoplastic material.
8. The method of claim 7 , wherein joining the first and second joint ends while the joint is under internal pressure so as to join the first and second rotor blade segments further comprises supplying heat to the joint, wherein the heat causes the at least one thermoplastic material of each of the first and second joint ends to join the first blade segment to the second place segment at their respective joint ends.