Composite Blade Laminate Thickness Transition Eccentricity

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Solution Overview

Problem

Existing solutions for modular blades with abrupt thickness changes in load paths fail to address the high stress levels and structural collapse due to pronounced eccentricities, which are not adequately managed by typical thickness transition slopes, leading to out-of-plane movements and potential structural failure.

Innovation Solution

Incorporating non-structural materials with low elastic modulus, such as foams or low modulus laminates, onto the mould face to modify the centroid alignment and increase the reaction length, thereby reducing eccentricity and out-of-plane stresses without adding structural weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If typical thickness transition slopes of 1:100 are used in modular blades with abrupt thickness changes (50-400%), then manufacturing simplicity is maintained, but high eccentricity in load centroid causes out-of-plane movements and structural collapse

Engineering Contradiction:
Improvethickness transition slopeVSAvoidstructural integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the slope parameter of the thickness transition from the typical 1:100 to a steeper slope (e.g., 1:10 or similar), fundamentally altering the geometric parameters to reduce the reaction length and thereby minimize the eccentricity effects in the load path

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a longitudinal slope to the thickness transition that was not present in conventional designs, creating a three-dimensional transition surface that simultaneously manages thickness change and load path alignment, reducing out-of-plane movements

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the thickness of the joining area is increased to accommodate metal elements and inserts, then adaptability and versatility are improved, but eccentricity in load centroid increases causing high stress levels

Engineering Contradiction:
Improveaccommodation of joining elementsVSAvoidstress level
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The patent changes the geometric parameters of the thickness transition, using a steeper slope to reduce the longitudinal distance over which the thickness changes, thereby minimizing the eccentricity moment arm and reducing stress levels despite the presence of thick joining areas

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the blade into modular sections with distinct thickness zones, allowing the joining area to be thick for accommodating elements while the transition zone manages the stress through controlled geometric changes

Inventive Principle:
Principle #1Segmentation

3Reliability

If a steeper thickness transition slope is used to reduce eccentricity effects, then structural integrity is improved, but manufacturing complexity and difficulty increase

Engineering Contradiction:
Improvestructural integrityVSAvoidtransition zone geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent establishes specific slope parameters (e.g., 1:10 or similar steep slopes) that balance structural integrity with manufacturability, providing clear quantitative guidelines that simplify the design process while maintaining safety

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4379205B1Transition of variable thicknesses of composite material laminates of a modular blade
Publication Date: 2025.07.09 NABRAWIND TECH SL
  • EP4379205B1 patent drawingFigure 1~2
  • EP4379205B1 patent drawingFigure 3~4
  • EP4379205B1 patent drawingFigure 5~6

AI summary

Transition of variable thicknesses of composite material laminates of a modular blade when the thickness varies by 50-400% and which smooths the centroid distribution, the centroid being represented as a function of the thickness and material of the laminate with respect to the corresponding radius of the blade. For this purpose, a non-structural material (10) is incorporated disposed on the lower part corresponding to the face of a mould (5) or the aerodynamic surface (11) is modified.