Polymer Concrete Mandrel for Wind Turbine Blades
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Solution Overview
Problem
Existing wind-turbine rotor blade production methods face challenges in achieving stability and weight reduction while maintaining structural integrity, particularly at the hub-side end pieces, where high static and dynamic loads occur, and require costly and time-consuming demolding processes.
Innovation Solution
The use of a polymer concrete rotor blade portion as a winding mandrel, which remains integrated into the rotor blade, allows for the winding of resin-impregnated fiber-composite laid scrims and spar caps, eliminating the need for a separable steel mandrel, reducing weight, and improving recyclability, with optional cast or spun flanges and inserts for threaded connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a separable steel mandrel is used for winding fiber-composite laid scrims, then the structural integrity and stability of the rotor blade can be ensured, but the production time increases due to required demolding processes and the weight of the rotor blade increases
Solution Approach 1:
The mandrel and the final rotor blade structure are merged into a single integrated component. The polymer concrete mandrel remains embedded within the rotor blade as the inner rotor blade portion, eliminating the need for separation. This merging allows the mandrel to become a permanent structural element rather than a temporary tooling component, thereby eliminating demolding time and reducing overall weight.
Solution Approach 2:
The polymer concrete mandrel serves as a disposable formwork that is intentionally left in place rather than removed. Unlike traditional steel mandrels that require complex demolding, the polymer concrete mandrel is designed to remain as part of the final structure, simplifying the production process and eliminating time-consuming removal operations.
2Ease of manufacture
If a separable steel mandrel is used for winding, then the structural stability can be maintained, but the production costs increase due to demolding processes and the need for separate handling
Solution Approach 1:
The mandrel is merged with the final rotor blade structure, becoming the inner rotor blade portion. This integration eliminates the need for separate demolding operations and handling procedures, thereby reducing production costs while maintaining structural stability through the embedded mandrel design.
Solution Approach 2:
The polymer concrete mandrel serves multiple functions: it acts as the winding form during manufacturing and simultaneously becomes a permanent structural component of the rotor blade. This self-service capability eliminates the need for separate tooling and reduces overall manufacturing complexity and cost.
3Productivity
If polymer concrete is used for the winding mandrel, then the recyclability and weight reduction are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The mandrel material is changed from traditional steel to polymer concrete, fundamentally altering the material parameters. This change enables the mandrel to be left embedded in the final structure, simplifying production and improving recyclability. The polymer concrete's properties allow for adequate precision without requiring the high tolerances of steel mandrels.
Solution Approach 2:
The use of polymer concrete, a composite material, for the mandrel provides a balance between manufacturing ease and structural performance. The composite nature of polymer concrete allows for sufficient dimensional stability and precision while being easier to manufacture and integrate into the final rotor blade structure.
4Reliability
If polymer concrete is used for the winding mandrel, then the mechanical properties such as chemical resistance are improved, but the initial structural strength may be reduced compared to steel
Solution Approach 1:
The polymer concrete mandrel utilizes composite material properties to achieve adequate strength while providing superior chemical resistance. The composite structure of polymer concrete offers corrosion and chemical resistance that steel cannot match, while maintaining sufficient mechanical strength for the winding process and final structural requirements.
Solution Approach 2:
The mandrel is merged with the fiber-composite rotor blade structure, creating a combined system where the polymer concrete mandrel and fiber-composite outer shell work together. This integration allows the mandrel to contribute to overall structural strength through its chemical resistance and dimensional stability, complementing the high-strength fiber-composite materials.
Data Source
AI summary
A wind-turbine rotor blade having a rotor blade portion which comprises an inner rotor blade portion with a first end having a plurality of fastening units for fastening to a hub of a wind turbine and a second end having a flange for fastening further portions of the wind-turbine rotor blade, wherein the inner rotor blade portion is produced from polymer concrete, wherein the rotor blade portion has a plurality of resin-impregnated fiber-composite laid scrims or rovings which are wound around the inner rotor blade portion.