Flow-Enhancing Fabric for Wind Turbine Spar Caps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current interlayer materials for wind turbine blades with carbon pultrusions fail to simultaneously provide optimal adhesion, electrical conductivity, fracture toughness, and permeability, leading to challenges in reinforcing large blades subjected to increased forces.
Innovation Solution
A flow-enhancing fabric with alternating layers of glass and carbon fibre bundles and monofilaments, arranged to ensure electrical conductivity and permeability, is used as an interlayer between precured fibre-reinforced elements in a spar cap, allowing for improved resin flow and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional interlayer materials are used between carbon pultrusions, then adhesion between layers is provided, but electrical conductivity and lightning protection are insufficient
Solution Approach 1:
The interlayer uses a composite structure combining carbon fibre bundles (for electrical conductivity and lightning protection) with glass fibre bundles (for adhesion and mechanical strength). This composite material approach allows simultaneous achievement of electrical conductivity, adhesion, and structural integrity that single-material solutions cannot provide.
Solution Approach 2:
The interlayer material has non-uniform distribution of fibre types: carbon fibre bundles are strategically placed to provide conductivity paths, while glass fibre bundles provide adhesion. This local quality variation allows different regions of the interlayer to fulfill different functions (conductivity vs. adhesion) simultaneously.
2Reliability
If carbon fibre bundles are used in the interlayer for conductivity, then electrical conductivity is improved, but transverse strength may be compromised
Solution Approach 1:
The interlayer combines carbon fibre bundles (providing electrical conductivity) with glass fibre bundles (providing transverse strength and adhesion). This composite structure allows the carbon fibres to conduct electricity while the glass fibres maintain mechanical strength, resolving the trade-off between conductivity and strength.
Solution Approach 2:
The interlayer optimizes the ratio and arrangement of carbon to glass fibre bundles to balance electrical conductivity and mechanical strength. By adjusting the parameters of fibre composition and distribution, the material achieves both conductivity and transverse strength requirements.
3Strength
If resin infusion is performed to bond carbon pultrusions, then structural integrity is improved, but resin flow efficiency is reduced by poor permeability
Solution Approach 1:
The interlayer is designed with controlled porosity and permeability characteristics that allow efficient resin flow through the carbon pultrusions during infusion. The fibre bundle arrangement and spacing create pathways for resin penetration while maintaining structural integrity after curing.
Solution Approach 2:
The interlayer parameters (fibre bundle spacing, porosity, thickness) are optimized to balance resin permeability and structural strength. The material allows sufficient resin flow during manufacturing while providing the structural integrity required for the final composite structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fabric enhances the transverse failure strength and electrical conductivity of the spar cap, providing a conductive path for lightning protection and efficient resin infusion, thus addressing the limitations of existing interlayer materials.
Implementation Method 1
the carbon fibres of the flow-enhancing fabric provides a conductive path between the two carbon elements sandwiching the flow-enhancing fabric and further provides potential equalisation between the two carbon elements. In this way, the flow-enhancing fabric protects the carbon elements against lightning strikes and flashovers.
Implementation Method 2
the fabric further comprises a plurality of monofilaments arranged between the first and second fibre layer along the transverse direction of the fabric, the plurality of monofilaments each having a mutual spacing between them
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
The present disclosure relates to a flow-enhancing fabric (1) extending in a longitudinal direction (6) and in a transverse direction (8), the fabric comprising a plurality of fibre layers (10, 20) including a first fibre layer (10) and a second fibre layer (20) arranged upon each other, the first fibre layer (10) comprising a first plurality of fibre bundles oriented in parallel in a first fibre direction (16) and comprising a plurality of first glass fibre bundles (14) and a number of first carbon fibre bundles (13), and the second fibre layer comprising a second plurality of fibre bundles oriented in parallel in a second fibre direction (26) different from the first direction (16) and comprising a plurality of second glass fibre bundles (24) and a number of second carbon fibre bundles (23), so that at least a number of first carbon fibre bundles (13) intersect and contact a number of second carbon (23) fibre bundles, and the fabric further comprises a plurality of monofilaments (30) arranged between the first and second fibre layer along the transverse direction of the fabric, the plurality of monofilaments (30) each having a mutual spacing (31) between them.