Laminate Test Specimen Structure for Realistic Rotor Blade Load Testing

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Solution Overview

Problem

Existing methods for manufacturing specimens for mechanical load testing of wind turbine rotor blade connections do not accurately replicate the real-world stress conditions, leading to suboptimal test results.

Innovation Solution

A method involving the creation of a laminate structure with embedded inserts, resin infusion, curing, and precise cutting to produce a specimen that mimics the actual installation scenario, featuring metal bushings surrounded by laminate and optionally core elements, allowing for realistic mechanical testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional specimen manufacturing methods are used, then manufacturing simplicity is maintained, but test realism and accuracy deteriorate

Engineering Contradiction:
Improvetest accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The laminate structure is divided into multiple sections with different insert configurations. A first section contains a single insert for realistic testing, while a second section contains multiple inserts for efficient manufacturing. This segmentation allows the specimen to replicate real-world single-insert conditions while maintaining manufacturing efficiency through multi-insert tooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple inserts are pre-installed in the laminate structure during manufacturing, and excess inserts are removed after curing. This preliminary action enables efficient production using standard multi-insert tooling while ensuring the final specimen contains only the required single insert, achieving both manufacturing efficiency and test realism.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple inserts are installed in laminate structure, then manufacturing efficiency is improved, but test specimen realism deteriorates

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidtest realism
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The laminate structure is divided into a first section with a single insert for realistic testing and a second section with multiple inserts for efficient manufacturing. This spatial segmentation allows different insert configurations to coexist in one laminate, enabling both manufacturing efficiency and test realism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Excess inserts are removed from the laminate structure after curing through cutting and extraction processes. This removal transforms the multi-insert manufactured structure into a single-insert test specimen, achieving realistic testing conditions while maintaining manufacturing efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If excess laminate and inserts are removed, then specimen precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvespecimen precisionVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The laminate structure is pre-cut along predetermined cutting lines that define the final specimen boundaries and separate sections with different insert configurations. This preliminary cutting action, performed after curing, simplifies the subsequent extraction of excess inserts and achieves precise specimen geometry with reduced processing complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Excess inserts and surrounding laminate are systematically removed after the curing and cutting stages. This extraction process, guided by predetermined cutting lines, achieves precise specimen geometry while maintaining manageable manufacturing complexity through structured removal sequences.

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

The method enables the production of specimens that closely resemble the real-world conditions of wind turbine rotor blade connections, resulting in improved mechanical test accuracy and reliability.

Implementation Method 1

resin infusion of the laminate structure, curing the laminate structure

Methodology Applied
Scientific EffectResin infusion:

Data Source

PatentEP4467955B1Method for manufacturing a specimen for mechanical load testing as well as specimen
Publication Date: 2025.11.26 NORDEX BLADE TECH CENT APS
  • EP4467955B1 patent drawingFigure 1
  • EP4467955B1 patent drawingFigure 2~3
  • EP4467955B1 patent drawingFigure 4a~4b

AI summary

The invention concerns a method for manufacturing a specimen (146) for a mechanical load testing. The method comprises the following steps: - providing a laminate structure (202), wherein the laminate structure (202) comprises at least three pairs (204a - 204e) of inserts embedded into laminate layers (203), wherein -- the laminate structure (202) has a first laminate end (206) and a second laminate end (208) being opposite to the first laminate end (206), -- the pairs (204a - 204e) of inserts are arranged adjacent to each other and parallel to each other, -- the inserts of a middle pair (204b, 204d) of inserts, being arranged between two adjacent pairs (204a, 204c, 204e) of inserts, are metal bushings (154, 156), - resin infusion and curing of the laminate structure (202), - cutting the cured laminate structure (202), and - removing - adjacent to the middle pair (204b, 204d) - the inserts or portions thereof, and thus producing at least one specimen (146) comprising the middle pair (204b, 204d) of inserts. The invention also concerns a specimen (146).