Segmented Mandrel Assembly for Easy Hollow Spar Beam Removal

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Solution Overview

Problem

Conventional mandrels for manufacturing wind turbine blades are difficult to remove after infusion, leading to deformation or degradation, which affects the quality and longevity of the hollow spar beams, and increases manufacturing costs due to frequent replacements.

Innovation Solution

A mandrel device composed of multiple rigid mandrel elements, each made of fibre-reinforced plastic or metal, with detachable attachment devices that allow for easy assembly and disassembly, enabling the mandrel to be collapsed inwardly for repeated use, thus maintaining quality and reducing the need for frequent replacements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a monolithic metal mandrel is used, then dimensional stability is improved, but removal difficulty increases

Engineering Contradiction:

Improvedimensional stabilityVSAvoidremoval ease

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The mandrel is divided into multiple detachable segments that can be assembled to form the complete mandrel structure. Each segment can be independently removed from the hollow spar beam after manufacturing, solving the removal difficulty while maintaining dimensional stability through the rigid material construction of each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mandrel transitions from a static monolithic structure to a dynamic assembly that can be configured in different states (assembled for manufacturing, disassembled for removal). The detachable segments allow the mandrel to change its configuration from a unified rigid structure to separable components.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If an inflatable mandrel is used, then removal ease is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveremoval easeVSAvoidhollow spar beam quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

Instead of using a single inflatable structure that deforms during moulding, the mandrel is segmented into rigid sections that maintain their shape and dimensional accuracy during the manufacturing process, while still allowing easy removal through detachment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention avoids using disposable foam mandrels that degrade after limited use. Instead, the detachable rigid segments can be reused multiple times without degradation, reducing long-term costs while maintaining manufacturing precision.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If a foam mandrel is used, then removal ease is improved, but reliability deteriorates

Engineering Contradiction:

Improveremoval easeVSAvoidmandrel durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention replaces the short-lived foam mandrel that degrades after around 30 moulding cycles with durable rigid segments that can be reused indefinitely. The detachable design allows complete removal and replacement of segments if needed, ensuring long-term reliability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The mandrel segments are constructed from rigid materials that combine dimensional stability with resistance to degradation. This composite approach using multiple material properties ensures the mandrel maintains its integrity and performance over many manufacturing cycles.

Inventive Principle:

Principle #40Composite materials

4Manufacturing precision

If a monolithic metal mandrel is used, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvehollow spar beam qualityVSAvoidmandrel structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mandrel is divided into multiple segments that can be manufactured separately and then assembled. This segmentation reduces the complexity of manufacturing each individual segment while maintaining the overall manufacturing precision through precise joining interfaces between segments.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12570063B2Mandrel device for manufacturing a segmented wind turbine blade

Publication Date: 2026.03.10 LM WIND POWER AS

AI summary

A mandrel device (50) for manufacturing a hollow spar beam (30) for a segmented wind turbine blade (10) in a mould (100), the mandrel device comprising:a plurality of mandrel elements (52, 53, 54, 55, 56, 57, 58, 59) each comprising a substantially rigid material, anda plurality of attachment devices (60) configured for detachably attaching adjacent mandrel elements,wherein the mandrel device has an assembled configuration and a detached configuration, wherein:in the assembled configuration, the plurality of attachment devices is engaged so that the plurality of mandrel elements is detachably attached to each other, and the plurality of mandrel elements extends along a longitudinal axis of the mandrel device so that the mandrel device has a substantially box shaped cross-section that varies along the longitudinal axis, andin the detached configuration, the plurality of attachment devices is disengaged so that the plurality of mandrel elements is detached from each other, and the plurality of mandrel elements is inwardly collapsible.