Application of Axial Carbon Fiber Fabric in Wind Turbine Blade Main Beams
A brief introduction to the application of axial carbon fiber fabric in wind turbine blade main beams.
Application of Axial Carbon Fiber Fabric in Wind Turbine Blade Main Beams
The main beam of a wind turbine blade serves as the blade's backbone, bearing the vast majority of bending loads. As blade lengths exceed 100 meters, traditional glass fiber struggles to meet the requirements for lightweight design and high stiffness; consequently, axial carbon fiber fabric has emerged as the dominant reinforcing material for the main beams of large-scale blades.
Functions and Structural Loading Characteristics of Wind Turbine Blade Main Spars
Functions of the Main Spar
The main spar serves as the structural backbone of the blade; it bears the vast majority of bending loads and constitutes the most critical load-bearing element within the blade's structure.
Bending Resistance: Resists bending moments generated by wind pressure.
Load Transmission: Transmits aerodynamic loads from the blade to the hub.
Deformation Control: Limits blade deflection to prevent impact with the tower.
Structural Loading Characteristics
Direction of Applied Force | Characteristics | Material Requirements |
0° Direction (Blade Lengthwise) | Primary bending direction; withstands tensile and compressive stresses | High tensile strength, high tensile modulus |
±45° Direction | Withstands shear stresses | Shear resistance |
90° Direction (Blade Widthwise) | Secondary load-bearing direction | Moderate reinforcement is sufficient |
The primary load on the main beam is oriented along the 0° direction; consequently, the material is required to possess exceptionally high strength and modulus in this specific direction—precisely where unidirectional carbon fiber fabric demonstrates its distinct advantage.
The Advantages of Unidirectional Carbon Fiber Fabric in Main Beams
Comparison Criteria | Carbon Fiber Axial Fabric | Glass Fiber |
Density | 1.6-1.8 g/cm³ | 2.5-2.6 g/cm³ |
Tensile Modulus | 230-640 GPa | 70-90 GPa |
Specific Modulus | High | Low |
Cost | High | Low |
Carbon fiber possesses a density approximately 35% lower than that of glass fiber, yet its modulus is 3 to 8 times greater, making it an ideal choice for simultaneously reducing weight and increasing stiffness in large-scale blades.
Specifications for Axial Reinforcement in Main Beams
Fiber Orientation
Primary Load-Bearing: 0° Unidirectional Fabric (400–600 g/m²)
Local Reinforcement: ±45° Biaxial Fabric (300–400 g/m²)
Fiber Grade
T700 Grade (230 GPa): Small to medium-sized blades; cost-sensitive applications
T800 Grade (294 GPa): The mainstream choice for large-scale blades
High-Modulus M-Series (>370 GPa): Ultra-long blades
Tow Size
12K: Small to medium-sized blades
24K, 48K: The mainstream choice for large-scale blades; offers high efficiency and low cost
60K and Above: Ultra-large blades
Molding Process
Process | Characteristics | Applications |
Vacuum Infusion | Suitable for ultra-large dimensions; low equipment investment | Dominant method for large-scale blades |
Prepreg Molding | Stable quality; requires hot-pressing equipment | Small to medium-sized blades or localized reinforcement |
Pultrusion | High fiber content; high efficiency | A new process developed in recent years |
Key Selection Points
Considerations | Recommendations |
Blade Length | <60m: All-fiberglass construction; 60–80m: Hybrid carbon-fiber/fiberglass; >80m: Carbon-fiber main beam |
Stiffness Requirements | High stiffness: Select high-modulus carbon fiber; Standard stiffness: Select T700-grade |
Cost Budget | Utilize large-tow fibers (48K, 60K) to reduce costs |
Molding Process | Vacuum infusion: Select dry fabric; Pultrusion: Select specialized yarns |
Environmental Conditions | Offshore wind applications require consideration of corrosion resistance |
Summary
Thanks to its superior performance in the 0° direction, straight fiber alignment, and design flexibility, carbon fiber axial fabric has become a core material for the main beams of large-scale wind turbine blades. Material selection requires careful consideration of blade length, stiffness requirements, and cost to determine the appropriate fiber type, tow specifications, and layup design.We are a carbon fiber fabric manufacturer based in China; for further information, please contact us via email at annayu@169chem.net or via WhatsApp at +8618909016373.