Wind Turbine Spar Cap Outer Frame Manufacturing

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Solution Overview

Problem

The manufacturing process for spar caps in wind turbine rotor blades faces challenges such as difficulty in transporting pultruded plates to molds and shifting during the resin infusion process, which complicates the conventional vacuum-assisted resin transfer molding (VARTM) method.

Innovation Solution

A method involving forming a thermoplastic fiber-reinforced outer frame via 3D pultrusion, thermoforming, or 3D printing, with structural materials arranged within the frame and infused with resin to create the spar cap, eliminating the need for conventional molds and allowing for easier handling and integration with existing rotor blades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional VARTM process with pultruded plates is used, then spar caps can be manufactured with structural integrity, but transportation of pultruded plates to molds becomes difficult and plates may shift during manufacturing

Engineering Contradiction:
Improvestructural integrity of spar capVSAvoidtransportation and positioning of pultruded plates
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spar cap is divided into two functional components: a pultruded outer frame providing structural integrity and a separately manufactured inner core. The outer frame is designed with integrated attachment features (ears, tabs, or extended edges) that serve as both structural elements and positioning features, eliminating the need to handle and position separate pultruded plates during assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner core material is placed inside the pultruded outer frame, creating a nested structure where the core is contained within the frame. This nesting approach allows the frame to serve as both the structural boundary and the positioning mechanism, preventing any shifting during the resin infusion process while maintaining structural integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If pultruded plates are used in conventional VARTM, then spar caps achieve required strength, but manufacturing process becomes complicated with shifting issues

Engineering Contradiction:
Improvestrength of spar capVSAvoidcomplexity of manufacturing process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The outer frame combines multiple functions into a single component: it provides the structural boundary, contains the inner core material, and includes integrated attachment features for positioning and securing. This merging eliminates the complexity of handling separate plates and their associated positioning mechanisms, simplifying the overall manufacturing process while maintaining strength.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional molds and infusion bags are used, then spar caps can be manufactured, but consumption of molds and consumable materials increases

Engineering Contradiction:
Improvemanufacturability of spar capVSAvoidconsumption of molds and consumable materials
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The pultruded outer frame is extracted as a pre-manufactured component with integrated functional features, eliminating the need for complex custom molds and infusion bags. The frame itself serves as the containment structure, replacing the traditional mold-infusion bag system and reducing consumption of these consumable materials.

Inventive Principle:
Principle #2Taking out (Extraction)

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 simplifies the manufacturing process by reducing the need for complex molds and consumable materials, enhancing the flexibility of spar caps, and enabling easier incorporation into conventional rotor blade manufacturing processes.

Implementation Method 1

forming an outer frame of the spar cap via pultrusion

Methodology Applied
Scientific EffectPultrusion: Extrusion

Implementation Method 2

The VARTM process is a technique that uses vacuum pressure to drive resin into a mold

Methodology Applied
Scientific EffectVacuum pressure: Vacuum

Data Source

PatentEP3787887B1Methods for manufacturing spar caps for wind turbine rotor blades
Publication Date: 2023.10.04 LM WIND POWER AS
  • EP3787887B1 patent drawingFigure 1
  • EP3787887B1 patent drawingFigure 2
  • EP3787887B1 patent drawingFigure 3

AI summary

The present disclosure is directed methods for manufacturing spar caps for wind turbine rotor blades. In certain embodiments, the method includes forming an outer frame of the spar cap via at least one of three-dimensional (3D) pultrusion, thermoforming, or 3D printing. As such, the outer frame has a varying cross-section that corresponds to a varying cross-section of the rotor blade along a span thereof. The method also includes arranging a plurality of structural materials (e.g. layers of pultruded plates) within the pultruded outer frame of the spar cap and infusing the structural materials and the outer frame together via a resin material so as to form the spar cap. The resulting spar cap can then be easily incorporated into conventional rotor blade manufacturing processes and/or welded or bonded to an existing rotor blade.