Turbomachine Blade Reinforcing Edge Roughening for Stronger Cohesion

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Solution Overview

Problem

Turbomachine blades face insufficient cohesion between the reinforcing edge and the blade body, leading to potential separation under mechanical stresses, particularly when made from composite materials that lack adequate resistance to impacts and abrasion.

Innovation Solution

A manufacturing method involving forging or machining of a titanium alloy blank with a Y-shaped profile, where the rough surface is modified by imprinting and deformation to enhance cohesion, using a combination of bending, stuffing, and spinning operations, and stamping to achieve the desired roughness for improved bonding with the blade body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a reinforcing edge is added to the blade body to improve resistance to impact and abrasion, then the blade's mechanical resistance is improved, but the cohesion between the reinforcing edge and blade body deteriorates, leading to potential separation under stress

Engineering Contradiction:
Improveresistance to impact and abrasionVSAvoidcohesion between reinforcing edge and blade body
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The method applies preliminary action by modifying the surface of the reinforcing edge blank before final assembly. The blank is deformed to create a rough surface topology that enhances bonding capability in advance, ensuring reliable cohesion when the reinforcing edge is attached to the blade body. This preemptive surface preparation prevents separation issues that would occur with smooth surfaces.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by creating a rough surface only on specific contact areas of the reinforcing edge blank that will bond with the blade body. The deformation process selectively modifies the surface topology at the bonding interface while leaving other surfaces intact, providing enhanced adhesion precisely where needed without affecting the overall geometry or aerodynamic surfaces.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the leading edge is made of composite material to reduce weight, then the blade mass is reduced, but the resistance to impact and abrasion deteriorates

Engineering Contradiction:
Improveblade massVSAvoidresistance to impact and abrasion
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The solution employs composite construction by combining a titanium alloy reinforcing edge with a composite material blade body. The titanium alloy providing superior mechanical resistance to impact and abrasion is strategically placed at the leading edge, while the composite material maintains overall blade lightness. This hybrid approach allows the blade to benefit from both material systems' advantages.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention applies local quality by using different materials in different locations: titanium alloy for the reinforcing edge at the leading edge where impact and abrasion resistance is critical, and composite material for the blade body where weight reduction is prioritized. This spatial differentiation of material properties optimizes both weight and mechanical resistance.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the reinforcing edge thickness is reduced to minimize material usage, then the amount of material is reduced, but the cohesive strength with the blade body deteriorates

Engineering Contradiction:
Improveamount of reinforcing edge materialVSAvoidcohesive strength with blade body
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The invention applies parameter changes by transforming the surface topology parameter of the reinforcing edge blank through deformation. By creating a rough surface with increased surface area and mechanical interlocking features, the effective bonding strength is enhanced without increasing the bulk material quantity. This surface parameter modification allows thin-walled structures to achieve high cohesive strength.

Inventive Principle:
Principle #35Parameter changes

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 increases the cohesive strength between the reinforcing edge and the blade body, enhancing the blade's resistance to mechanical stresses and ensuring robustness, while being cost-effective and easily integratable into production lines.

Implementation Method 1

The method includes an additional step consisting in deforming at least the rough surface of the blank so as to obtain the final shape of the reinforcing edge

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3038791B1Method for producing a blade reinforcing edge
Publication Date: 2022.11.16 SAFRAN AIRCRAFT ENGINES SAS
  • EP3038791B1 patent drawingFigure 1~4

AI summary

method for producing a reinforcing edge (10') of a blade of a turbomachine (70), which involves providing a blank (10) of the reinforcing edge and printing an imprint on said blank, in such a way as to form a rough surface (S). A reinforcing edge (10') obtained by such a method.