Substrate Bending and Adhesive Joint Peel Strength Testing

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Solution Overview

Problem

Wind turbine blades experience deformation and stress due to bending moments during operation, leading to potential failure of components such as shear webs and adhesive joints, which can reduce the service life of the blade.

Innovation Solution

An apparatus and method for determining the bending strength of substrates and peel strength of joints by using a fixture with support beams and load applying members to simulate deformation under load, equipped with sensors to measure parameters like axial load, peel stress, and bending moments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If wind turbine blades are subjected to bending moments during operation, then the blades can generate lift force and torque for electricity production, but the bending moments cause deformation and stress that lead to component failure and reduced service life

Engineering Contradiction:
Improveelectricity generationVSAvoidservice life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by conducting strength determination tests on substrate and joints before installing the wind turbine blade. The test apparatus simulates operational bending moments and loads to pre-assess the structural integrity of the substrate and adhesive joints. This preliminary testing identifies potential failure points before the blade enters service, allowing for corrective measures to be taken in advance, thus preventing future component failure while maintaining the blade's power generation capability

Inventive Principle:
Principle #10Preliminary action

2Power

If the blade structure is designed to withstand high bending moments for power generation, then electricity production is improved, but the complexity of testing and determining strength parameters increases

Engineering Contradiction:
Improvelift force generationVSAvoidtesting apparatus complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the strength determination into distinct components: substrate bending strength testing and joint peel strength testing. The test apparatus is segmented into separate functional modules including support beams for substrate testing, fixture for joint testing, and independent load applying mechanisms. This segmentation allows each component to be tested independently with specialized equipment, reducing overall system complexity while comprehensively assessing the blade's power generation capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses sensors as intermediary devices to measure strength parameters indirectly. Instead of directly measuring complex stress distributions throughout the blade structure, sensors are placed at critical locations to measure substrate deflection, joint separation, and load parameters. These intermediary measurements are then used to calculate the strength parameters, simplifying the testing apparatus while maintaining accuracy for power generation assessment

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If sensors are used to measure strength parameters during testing, then measurement precision is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvestrength parameter measurementVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by placing sensors only at critical locations where strength parameters need to be measured, rather than throughout the entire blade structure. Sensors are strategically positioned to measure substrate deflection at the loading point, joint separation at the adhesive interface, and reaction forces at the support points. This localized sensing approach achieves precise measurement of strength parameters while minimizing the number of sensors required, thus reducing device complexity and cost

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4056980B1System and method for determining strength of a structure
Publication Date: 2025.10.29 LM WIND POWER AS
  • EP4056980B1 patent drawingFigure 1
  • EP4056980B1 patent drawingFigure 2
  • EP4056980B1 patent drawingFigure 3~5

AI summary

The present invention relates to a apparatus for determining at least one a bending strength of a substrate and peel strength of a joint between a structure and the substrate. The apparatus includes a fixture configured to support the structure and a plurality of support beams positioned on either sides of the fixture and configured to support the substrate. Further, the apparatus includes a plurality of load applying members, which are configured to apply load onto the substrate to deform the substrate relative to the plurality of support beams. Furthermore, the apparatus includes a sensor, which is configured to determine parameters such as axial load induced in the structure, peel stress in the joint between the substrate and the structure and bending moments on the substrate during application of load onto the substrate, to determine at least one of the bending strength and the peel strength.