Thermal Welding of Wind Turbine Blades

Stage: Development

Modern wind turbine blades commonly are manufactured in several key components and bonded together with an adhesive. Over a wind turbine’s lifespan, its blades suffer static and cyclic fatigue loads that can cause adhesive-joint failure leading to blade structural collapse. Wind turbine blades are typically constructed of glass, carbon fibers, or both and a thermoset resin such as epoxy. However, with the recent development of a two-part acrylic-based reactive thermoplastic resin system, thermoplastic resins may offer a replacement for thermosets. A significant advantage of thermoplastic composites is the potential for fusion welding, which could eliminate the need for adhesive bonds, increase the blades’ overall strength, improve their reliability, and reduce manufacturing costs and time. Fusion bonding takes advantage of thermoplastic matrices’ easily accessible glass-transition temperature to weld separate components through a solid-fluid-solid phase-transition sequence.



Researchers at the National Renewable Energy Laboratory (NREL) have developed a thermal welding device, method, and system to construct wind turbine blades that are designed with a reactive thermoplastic resin. However, state-of-the-art manufacturing tolerances allow 1 – 20-mm contact gaps that are filled with adhesive. As the current blade-joint designs do not easily enable welding, the joints can be redesigned to allow sufficient contact in places where welds will be made.


The redesigned joints facilitate the implementation of welding methods that do not require a cost-prohibitive tightening of blade tolerances. Thermal welding of thermoplastic composite wind turbine blades has the potential to replace adhesives and to enable lower cost, more structurally durable blades. Operating expenditures possibly can be reduced with decreased blade-mold cycle time, with thermoplastic room-temperature cure, and with the recyclability of thermoplastic resins. Moreover, researchers at NREL have demonstrated superior mechanical robustness, such as enhanced failure strength and increased fatigue lifetime, of thermally welded bonds over traditional adhesive bonds when tested in lap-shear.


To learn more about Thermal Welding of Wind Turbine Blades, please contact Erin Beaumont at:


Erin.Beaumont@nrel.gov


ROI 18-123

Applications and Industries

  • Wind-turbine blade manufacturing
  • Automotive components and manufacturing
  • Marine components and manufacturing
  • Aerospace components and manufacturing
  • Other transportation components and manufacturing
  • Pipe and tank components and manufacturing
  • Building components and manufacturing
  • Infrastructure components and manufacturing

Benefits

  • Possible enhanced failure strength and prolonged fatigue lifetime of wind-turbine blade joints
  • Possible reduction in manufacturing operating expenditures with increased blade-mold throughput
  • No need for tighter manufacturing tolerances to implement thermal welding
  • Thermal welding brackets may be added at multiple production-sequence points to accommodate existing manufacturing protocols.