Composite Turbine Blade Metal Reinforcement Fillet Stress

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Solution Overview

Problem

Composite material blades for turbomachines, such as aircraft OGVs, face mechanical strength challenges due to stress concentration at connection fillets between the blade and platforms, leading to potential rupture zones.

Innovation Solution

A method for manufacturing composite material blades that includes integrating a second metal reinforcement on the intrados and extrados portions of the platforms and in the decoupling areas, which helps to reinforce the connection fillets and reduce stress concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a composite material blade is manufactured with metal reinforcement only on the leading edge, then the blade protects against erosion and impacts, but stress concentration occurs at the connection fillets between the blade and platforms

Engineering Contradiction:
Improveerosion and impact protectionVSAvoidmechanical strength at connection fillets
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies local quality by placing metal reinforcement specifically at the connection fillets between the blade and platforms, where stress concentration occurs. This localized reinforcement targets the weak points without unnecessarily reinforcing the entire blade structure, thereby improving strength at critical locations while maintaining overall design efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining metal reinforcement with the composite blade structure at the connection fillets. This hybrid approach leverages the high strength and stiffness of metal in stress-concentrated areas while maintaining the lightweight and corrosion-resistant properties of the composite material in the rest of the blade.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If the platform opening is not limited, then the manufacturing process is simpler, but the mechanical stresses experienced by the OGV increase

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmechanical stresses on OGV
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

The patent applies local quality by providing metal reinforcement specifically at the connection fillets where stress concentration occurs. This localized approach addresses the stress issue without requiring complex changes to the overall platform structure or manufacturing process, thereby maintaining ease of manufacture while reducing mechanical stresses.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If thermoplastic resin is used to form the OGV core, then the manufacturing process is simplified, but the mechanical properties are weaker than conventional armor

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmechanical properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses composite materials by combining thermoplastic resin with metal reinforcement at the connection fillets. This hybrid composite structure leverages the manufacturing simplicity of thermoplastic resin while compensating for its weaker mechanical properties through strategic metal reinforcement, achieving both ease of manufacture and adequate strength.

Inventive Principle:
Principle #40Composite materials

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 integration of the second metal reinforcement effectively reduces stresses in the connection fillets, enhances mechanical robustness, and improves the distribution of forces, thereby increasing the critical buckling force of the blade.

Implementation Method 1

of polymerizing the resin so as to form the blade

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP4136325B1Blade made of composite material with metal reinforcements, and method of manufacturing such a blade
Publication Date: 2025.06.04 SAFRAN SA
  • EP4136325B1 patent drawingFigure 1~4
  • EP4136325B1 patent drawingFigure 5~8
  • EP4136325B1 patent drawingFigure 9

AI summary

The invention relates to a method for manufacturing a blade (100) made of composite material for a turbine engine, in particular of an aircraft, comprising the steps consisting in: - injecting a resin in order to impregnate a fibrous preform woven in three dimensions; - polymerising the resin so as to form the blade (100) comprising an aerofoil (102), one longitudinal end of which is connected to a platform (112, 114), the platform comprising pressure (116) and suction (118) portions connected to said aerofoil by a fillet (120), a separation (122) being formed in the fibrous preform between the pressure and suction portions; reinforcing a leading edge of the aerofoil; and reinforcing the fillets by integration of a metal reinforcement (126) on at least one part of the pressure and suction portions of the platform and in the separation.