Retractable Mandrel Tool for Internal Wind Blade Laminate Joining

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Solution Overview

Problem

The manufacture of large wind turbine blades is challenging due to difficulties in controlling the glue line quality and safety hazards in the gluing process, as well as the difficulty in fitting and positioning mandrel tools within blade sections.

Innovation Solution

A method involving a mandrel tool with retractable portions that reduces its cross-section to fit inside blade sections, supports a fiber lay-up, and infuses resin to form a laminate joint, allowing for a strong and lightweight connection between blade sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If adhesive bonding is used to connect blade sections, then the joining process is simpler, but the weight-to-strength performance deteriorates and glue line quality control becomes difficult

Engineering Contradiction:

Improvejoining process simplicityVSAvoidweight-to-strength performance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the fundamental parameter of the joining method from adhesive bonding to resin infusion curing. This transforms the chemical process from applying external adhesive to infusing resin through the fiber lay-up, enabling better control over the bonding process and achieving superior weight-to-strength performance through integrated fiber-resin structure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical adhesive application process with a controlled resin infusion system. Instead of manually or mechanically applying adhesive to surfaces, the system uses vacuum-assisted resin transfer molding (VARTM) to infuse resin through the dry fiber lay-up, eliminating glue line quality issues and improving structural performance

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If a rigid mandrel tool is used to support fiber lay-up, then the fiber positioning is accurate, but the difficulty of fitting and positioning the mandrel inside blade sections increases

Engineering Contradiction:

Improvefiber positioning accuracyVSAvoidmandrel fitting and positioning

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention transforms the rigid mandrel tool into a dynamic, adaptable structure by introducing collapsible sections that can change their cross-sectional dimensions. The mandrel can be collapsed to a smaller size for easy insertion into blade sections, then expanded to provide accurate fiber positioning support during the resin infusion process

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The mandrel tool is divided into multiple collapsible sections that can independently adjust their dimensions. This segmentation allows the mandrel to be compressed to a compact form for insertion, then expanded to its full functional size for fiber support, solving both the fitting difficulty and positioning accuracy requirements

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If blade sections are joined from outside the blade cavity, then the process is more accessible, but certain joining processes such as web connection cannot be performed

Engineering Contradiction:

Improveprocess accessibilityVSAvoidjoining process options

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The invention inverts the traditional approach by performing the joining process from inside the blade cavity rather than from outside. The collapsible mandrel is inserted through the blade cavity, allowing fiber lay-up and resin infusion to proceed from the interior, enabling web connections and other internal joining methods that are inaccessible from the exterior

Inventive Principle:

Principle #13The other way round (Inversion)

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

This method provides a strong and lightweight laminate joint with improved weight-to-strength performance, enabling safer and more efficient manufacturing by allowing the joining process to be performed from within the blade cavity.

Implementation Method 1

infusing at least a portion of the fiber lay-up with a resin and curing the resin to obtain a cured joining portion joining the blade sections inside

Methodology Applied

Scientific EffectResin infusion:

Implementation Method 2

curing the resin to obtain a cured joining portion

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS12479179B2Mandrel tool

Publication Date: 2025.11.25 SIEMENS GAMESA RENEWABLE ENERGY AS

AI summary

A method for manufacturing a wind turbine blade is provided, including the steps of: a) arranging a fiber lay-up on a mandrel tool, the mandrel tool including a frame and, as seen in cross-section, at least two mandrel portions connected to the frame, and wherein at least a portion of the fiber lay-up is supported by an outer surface of the at least two mandrel portions, b) reducing a cross-section size of the mandrel tool by retracting at least one of the mandrel portions towards the frame, c) arranging the mandrel tool inside adjacent blade sections, d) increasing the cross-section size of the mandrel tool by extending at least one of the mandrel portions away from the frame, and e) infusing at least a portion of the fiber lay-up with a resin and curing the resin to obtain a cured joining portion joining the blade sections inside.