Adhesive Joint Assembly Using a Flexible Glue Dam to Prevent Notches

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Solution Overview

Problem

Existing methods for joining structures with adhesives often result in notch formation at the bond line, which weakens the joint, particularly in wind turbine rotor blades subjected to significant stress over time.

Innovation Solution

Incorporating a flexible adhesive limiting member that acts as a 'glue dam' to contain the adhesive within the joint, forming a concave front line surface and preventing notches by limiting the adhesive's spread, thereby ensuring a strong and notch-free bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If liquid adhesive is applied to join structures, then the structures are bound together, but the adhesive spills outward forming a convex front line surface that creates notches at the interface

Engineering Contradiction:
Improvejoint strengthVSAvoidfront line surface smoothness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A flexible adhesive limiting member is introduced as an intermediary element between the adhesive and the surrounding medium. This member acts as a glue dam that controls adhesive flow and defines a smooth front line surface, preventing the adhesive from spilling outward and forming notches at the interface between the adhesive and structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive limiting member is made of flexible material that can conform to the joint geometry while maintaining its function as a barrier. The flexibility allows it to adapt to different joint configurations while still preventing adhesive overflow and defining a clean front line surface.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If adhesive is allowed to spread freely, then complete coverage is achieved, but notches form at the bond line front weakening the joint

Engineering Contradiction:
Improvejoint reliabilityVSAvoidbond line strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The flexible adhesive limiting member serves as a mediator that controls the adhesive's interaction with the surrounding medium. It allows complete coverage within the joint while preventing overflow that would create notches, thus maintaining both reliability and strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive limiting member is positioned in advance to prevent the harmful effect of adhesive spillage before it occurs. By establishing a physical barrier at the bond line front, it preemptively stops the formation of notches that would weaken the joint.

Inventive Principle:
Principle #9Preliminary anti-action

3Strength

If more adhesive is used to ensure complete filling, then the joint is more robust, but adhesive spills outward creating convex front line surface and notches

Engineering Contradiction:
Improvejoint robustnessVSAvoidadhesive front line quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The adhesive limiting member acts as a mediator that decouples the relationship between adhesive quantity and front line quality. It allows sufficient adhesive to be used for robust joint formation while preventing excess adhesive from spilling outward and degrading the front line quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible nature of the limiting member allows it to accommodate variations in adhesive volume while maintaining a consistent smooth front line surface, enabling complete filling without spillage.

Inventive Principle:
Principle #30Flexible shells and thin films

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 flexible adhesive limiting member effectively reduces adhesive usage, prevents notches, and enhances the joint's durability by maintaining a smooth, defined adhesive front line surface, improving the structural integrity of wind turbine rotor blades.

Implementation Method 1

a flexible adhesive limiting member extending between said structures; wherein the flexible adhesive limiting member functions as a glue dam whereby the adhesive is limited by the flexible adhesive limiting member such that a concave front line surface of the adhesive is defined

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2334932B2Assembly and method of preparing an assembly
Publication Date: 2024.05.01 VESTAS WIND SYSTEMS AS
  • EP2334932B2 patent drawingFigure 1~2
  • EP2334932B2 patent drawingFigure 3~4
  • EP2334932B2 patent drawingFigure 5~6

AI summary

The invention relates to a method of preparing an assembly, comprising providing a first structure; providing a second structure; providing at least one flexible adhesive limiting member extending between said structures; and providing an adhesive between said structures to bind said structures to each other; wherein the adhesive is limited by the flexible adhesive limiting member such that a concave front line surface of the adhesive is defined. The invention also relates to such an assembly as well as to a wind turbine rotor blade, and to a wind turbine, comprising such an assembly.