Wind Turbine Blade Tension Fabric Pretensioning

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Solution Overview

Problem

Modern wind turbine rotor blades are heavy and difficult to transport and assemble due to their size, shape, and weight, and maintaining optimal pretension in the tension fabric skin is crucial for both aerodynamic and structural performance, which is challenging with existing technologies.

Innovation Solution

The design incorporates a self-supporting structural framework with span-wise and chord-wise members, a fabric skin, and mechanical elements like stiffeners and tensioning screws that allow for relative movement to adjust the aerodynamic contour and provide pretension to the fabric skin, ensuring structural and functional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional molded composite wind blades are used, then structural strength is achieved, but weight and transportation difficulty increase significantly

Engineering Contradiction:

Improvewind blade weightVSAvoidstructural strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent replaces traditional rigid molded composite shells with tension fabric skins that form flexible thin-walled structures. The fabric skin is stretched over a self-supporting framework and pretensioned to maintain structural integrity, achieving wind blade construction with significantly reduced weight while maintaining necessary strength through tension-based load carrying rather than rigid shell resistance

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent extracts the load-carrying function from the outer shell and transfers it to the internal self-supporting framework. The framework includes span-wise members and chord-wise members that provide primary structural support, while the fabric skin serves primarily as an aerodynamic surface, separating structural strength requirements from weight reduction goals

Inventive Principle:

Principle #2Taking out (Extraction)

2Use of energy by moving object

If tension fabric skin is used to reduce weight, then aerodynamic performance improves, but maintaining optimal pretension becomes challenging

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidpretension maintenance

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent implements adjustable pretension mechanisms including turnbuckles, tensioning screws, and hydraulic actuators that allow dynamic adjustment of fabric skin tension. This enables optimization of pretension levels for different operating conditions and maintains aerodynamic efficiency throughout the wind blade's operational life, addressing the challenge of maintaining optimal pretension under varying loads and environmental conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent incorporates sensors and monitoring systems that detect fabric skin tension levels and provide feedback to control systems. This enables automatic adjustment of pretension through actuated tensioning mechanisms, ensuring optimal aerodynamic performance is maintained without manual intervention and allowing real-time adaptation to changing operational conditions

Inventive Principle:

Principle #23Feedback

3Productivity

If large panel sizes are used for wind blades, then manufacturing efficiency improves, but required pretension amount increases significantly

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidpretension force

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The patent divides the wind blade structure into modular segments including separate fabric skin panels and discrete framework members. This segmentation allows for manageable assembly of large-scale structures while distributing pretension requirements across multiple localized tensioning points rather than requiring excessive uniform tension across entire large panels, reducing total pretension force while maintaining structural integrity

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If self-supporting framework with adjustable members is implemented, then aerodynamic contour adjustment is enabled, but device complexity increases

Engineering Contradiction:

Improveaerodynamic contour adjustabilityVSAvoidstructural framework complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the self-supporting framework members to serve multiple functions: providing primary structural support, enabling aerodynamic contour adjustment through relative movement, and facilitating pretension application to the fabric skin. This multi-functionality reduces overall device complexity by consolidating several functions into unified structural elements rather than requiring separate systems for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9803617B2Method and system for tensioning tension fabrics in wind-turbine

Publication Date: 2017.10.31 GE INFRASTRUCTURE TECH LLC

AI summary

A wind blade includes a self-supporting structural framework, having a span-wise member, a plurality of chord-wise members, a fabric skin, and at least one of a stiffener and a mechanical element. The plurality of chord-wise members is coupled to the span-wise member and each chord-wise member and the span-wise member maintains an aerodynamic contour of the wind blade. Further, the fabric skin is disposed over the self-supporting structural framework. The stiffener and/or the mechanical element are coupled to the self-supporting structural framework, and are operable to provide a relative movement to the self-supporting structural framework for adjusting the aerodynamic contour and provide pretension to the fabric skin.