Wind Turbine Blade Fastener Sleeves for Liquid Ingress Control

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Solution Overview

Problem

Existing fastener assemblies for wind turbine blade to rotor hub connections fail to effectively prevent the ingress of liquids, leading to reduced fatigue life and potential structural failure due to loss of preload and separation of blade root inserts.

Innovation Solution

A fastener assembly with sleeves configured to absorb liquid ingress at a non-threaded portion, which are inserted into the blade root insert, providing a simple and reliable sealing solution that reduces maintenance and replacement costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealant products or rubber gaskets are used to seal the blade root insert, then sealing performance is improved, but liquid ingress still occurs due to volume changes during solidification or assembly tolerances

Engineering Contradiction:

Improvesealing performanceVSAvoidliquid ingress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a porous polymeric material that absorbs liquid through capillary action. The material's porous structure allows it to actively draw in and retain liquid that penetrates through assembly tolerances or bypasses the sealant, providing a secondary absorption mechanism that complement the primary sealant barrier.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The invention combines a sealant product (primary sealing barrier) with a polymeric absorption material (secondary absorption layer). This composite approach creates a multi-layer defense system where the sealant prevents most liquid ingress while the polymeric material absorbs any liquid that penetrates, addressing both the sealant's volume change issue and assembly tolerance gaps.

Inventive Principle:

Principle #40Composite materials

2Power

If larger rotor blades are used to extract more energy from wind, then energy extraction is improved, but stresses at the blade root connection increase leading to higher failure risk

Engineering Contradiction:

Improveenergy extractionVSAvoidblade root connection strength

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The patent applies a protective absorption layer beforehand in the blade root insert to cushion against liquid ingress that could compromise the mechanical connection. This preventive measure ensures that even under high stresses from larger blades, the connection remains protected from liquid-induced degradation that would accelerate fatigue and reduce strength.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention changes the physical state and properties of the protective material from a liquid sealant to a solid polymeric absorption material. This parameter change allows the material to maintain its sealing and absorption functions under the high stress conditions and extreme events experienced by larger rotor blades, providing more reliable protection.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional sealants are applied to prevent liquid ingress, then sealing is improved, but the sealant volume changes during solidification creating gaps

Engineering Contradiction:

Improvesealing effectivenessVSAvoidsealant filling completeness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses a disposable polymeric absorption material as a secondary line of defense. This material is designed to be consumed or saturated over time as it absorbs liquid, providing reliable backup protection without requiring precise manufacturing tolerances. When saturated, it can be replaced during maintenance, ensuring continuous protection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The porous structure of the polymeric material allows it to flexibly accommodate volume changes and gaps that occur during sealant solidification. The porous network can expand and contract to fill voids and maintain contact with the blade root insert surfaces, ensuring complete coverage even when the sealant shrinks during curing.

Inventive Principle:

Principle #31Porous materials

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 solution significantly reduces liquid ingress, extending the working life of connection components and lowering maintenance costs, while being easily installable and cost-effective, with minimal material requirements.

Implementation Method 1

The fastener includes one or more sleeves configured to absorb ingress of liquid into the blade root insert

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

sleeves configured to absorb ingress of liquid into the blade root insert

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS11846266B2Fastener assembly, wind turbine hub assembly and related methods

Publication Date: 2023.12.19 LM WIND POWER AS

AI summary

The present disclosure relates to fastener assemblies (400) for a wind turbine blade (22) to rotor hub (20) connection, wherein the fastener assembly (400) comprises a fastener (401) and one or more sleeves (410) configured to absorb the ingress of liquid into a blade root insert (220). The present disclosure also relates to wind turbine hub assemblies (1000) and associated methods (700).