SARTEX: The First 45-Meter-long Wind Turbine Blade beam was Successfully Cast using the Polyurethane Resin Vacuum Infusion Process

 

At the German Aerospace Center in Stade, project partners SAERTEX and resin manufacturer Covestro have successfully cast the first 45-meter-long wind turbine blade beam in cooperation with each other.

 

The continuous expansion of wind farms is accompanied by larger wind turbine components. To meet future requirements, the quality and process performance of the components must be continuously optimized. Therefore, we need to optimize the relationship between glass fiber and carbon fiber reinforcements, composite materials, axial cloth layup systems and production technology. The SAERTEX non-bend glass fiber fabric was previously saturated with an epoxy resin system and now has been adapted to the polyurethane resin system of the resin manufacturer Covestro in a groundbreaking way.

 

Like epoxy resins, polyurethane resins have a lower density. The mold of the 45-meter-long beam can be produced on the mold of the German Aerospace Center. Each beam surface is a uniform structural design with 44 layers of unidirectional fabric.

“The beam is the most important part of the wind turbine blade.” Mr. Marc Schrief, General Manager of SAERTEX, introduced, “It bears the entire wind resistance. A more rigid beam means better wind power output. This example proves that we can perfectly match the fabric design with customer needs. Since the glass fiber fabric is well impregnated, the carbon fabric can also obtain such good process performance. This will enable this technology to be promoted to wind turbine blades over 100 meters.”

 

Kim Mr. Klausen, Project Manager at Covestro, pointed out professionally from the resin perspective: “Polyurethane resin gives us two more obvious advantages over epoxy resin. Stability and durability are the ultimate requirements for blade quality. In this experiment, a higher glass transition temperature and smaller dimensional shrinkage than epoxy were obtained. In addition, polyurethane reaction releases less heat.

 

SAERTEX has accumulated a lot of research and testing experience, and continuously optimized the compatibility between glass fiber non-bend fabric, core material and polyurethane resin. Therefore, SAERTEX has been able to ensure the advantage of rapid impregnation of polyurethane resin by optimizing the production of fabric. SAERfoam, a GL-certified core material, also shows good process performance for compatibility with polyurethane resin impregnation.

 

SAERTEX General Manager Mr. Marc Schrief is very optimistic about the progress of the cooperation project: “The current achievement is that we have increased the production of blades by optimizing the production of fabrics and developing a faster resin vacuum infusion process. But we have further ideas and opinions for the wind energy field: We understand that balsa wood is not an ideal material for the future.

 

As a natural resource, balsa wood does not have uniform quality and contains moisture. This is absolutely not compatible with polyurethane resin. Our structural core material SAERfoam is made of ultra-light polyurethane foam and reinforced with glass fiber long fiber 3D space structure, which is one of the innovative ways to replace balsa wood.