Composite Turbomachine Blade Root Reinforcement Using Fiber Cuts

Solution Overview

Problem

Existing composite turbomachine blades face challenges with high stress levels at the blade root area, inadequate local reinforcement, and insufficient stiffness, particularly in unducted turbomachines, leading to increased mass and risk of buckling.

Innovation Solution

A reinforcement for composite turbomachine blades using a mixture of fiber cuts and a tackifier, comprising epoxy resin solubilized in a solvent, is arranged in the inner cavity to close the opening between spaced inner end portions of the blade skins, providing enhanced mechanical strength and stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the blade is designed with organic matrix composite material to reduce mass, then the mass of the blade is reduced, but the stress levels at the blade root area increase and the stiffness is insufficient

Engineering Contradiction:

Improvemass of the bladeVSAvoidstiffness of the blade

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by introducing a reinforcement element specifically at the blade root area where stress concentrations occur. This reinforcement is localized to the region needing additional strength, rather than uniformly distributing mass throughout the entire blade. The reinforcement comprises a mixture of fiber cuts and tackifier that provides targeted structural support at the critical root section, addressing the insufficiency of stiffness in that specific area while maintaining the overall mass reduction benefits of the composite material design.

Inventive Principle:

Principle #3Local quality

2Productivity

If the blade dimensions are increased to improve performance, then the bypass ratio increases, but the mass of the blades increases

Engineering Contradiction:

Improvebypass ratioVSAvoidmass of the blades

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The patent utilizes composite materials by employing an organic matrix combined with fiber reinforcement (in the form of fiber cuts and tackifier mixture) to create a blade that achieves both lightweight construction and adequate structural strength. This composite approach allows the blade to be larger in dimension for improved bypass ratio while maintaining reduced mass through the use of high-performance composite materials that provide strength-to-weight ratio advantages over traditional metallic materials.

Inventive Principle:

Principle #40Composite materials

3Strength

If the blade root area is reinforced to reduce stress concentrations, then the strength is improved, but the mass of the blade increases

Engineering Contradiction:

Improvestrength of the blade root areaVSAvoidmass of the blade

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by introducing a reinforcement element specifically at the blade root area where stress concentrations occur. This reinforcement is localized to the region needing additional strength, rather than uniformly distributing mass throughout the entire blade. The reinforcement comprises a mixture of fiber cuts and tackifier that provides targeted structural support at the critical root section, addressing the insufficiency of stiffness in that specific area while maintaining the overall mass reduction benefits of the composite material design.

Inventive Principle:

Principle #3Local quality

4Ease of manufacture

If traditional insert materials are used to fill the inner cavity, then the manufacturing is simplified, but the stiffness and stress resistance are insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstiffness and stress resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent utilizes composite materials by employing an organic matrix combined with fiber reinforcement (in the form of fiber cuts and tackifier mixture) to create a blade that achieves both lightweight construction and adequate structural strength. This composite approach allows the blade to be larger in dimension for improved bypass ratio while maintaining reduced mass through the use of high-performance composite materials that provide strength-to-weight ratio advantages over traditional metallic materials.

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 reinforcement effectively reduces stress concentrations, limits mass increase, and enhances the overall stiffness of the blades, reducing the risk of buckling and improving frequency placement.

Implementation Method 1

a tackifier, in particular comprising an epoxy resin solubilized in a solvent

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

the tackifier comprising an epoxy resin solubilized in a solvent

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS20250215801A1Reinforcement for a composite blade of a turbomachine, comprising a mixture of fiber cuts and a tackifier

Publication Date: 2025.07.03 SAFRAN SA

AI summary

The present invention concerns a reinforcement for a blade of a turbomachine, the blade comprising a first outer skin and a second outer skin which are made of composite material each comprising an inner end portion spaced apart from each other in such a way as to delimit therebetween an inner cavity of the blade that opens into an opening at an inner end of the blade, the inner end being radially opposite the outer end, wherein the reinforcement is adapted to be arranged in the inner cavity in such a way as to close the opening, and wherein the reinforcement comprises a mixture of cuts of at least one fiber and a tackifier, the cuts having lengths comprised between 1 mm and 15 mm, the tackifier comprising an epoxy resin solubilized in a solvent.