Composite Annular Casing Reinforcement for Turbomachine Compressor Flanges

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Solution Overview

Problem

Existing composite annular casings for turbomachines face weaknesses at the junctions of radial annular flanges and circular walls due to rounding issues during manufacturing, leading to reduced mechanical resistance, especially at sharp edges, and require expensive tools or heterogeneous fiber distribution.

Innovation Solution

A composite annular casing design featuring a braided or woven auxiliary reinforcement with a triangular cross-section, aligned fibers, and uniform fiber density, which contacts the main reinforcement over the entire radial and axial thickness, providing homogeneous fiber distribution and reinforcing the sharp edge area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a stacked preform is used to form the composite housing, then the housing can be manufactured with flanges and cylindrical sections, but the stacked preform forms a rounded edge at the mold edge leaving a void that is filled with resin without fiber reinforcement, creating a weak point

Engineering Contradiction:
Improvemanufacturability of composite housingVSAvoidstrength at the junction of flange and wall
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention applies preliminary action by placing an auxiliary fibrous reinforcement in the form of a cord or strand at the location where the sharp edge will be formed, before the main preform is placed in the mold. This preliminary placement ensures that fibers are present at the critical junction area to reinforce the sharp edge and prevent the formation of weak points caused by void filling during injection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by using a different fibrous reinforcement configuration at the critical junction area compared to the rest of the housing. The auxiliary reinforcement (cord or strand) is specifically placed at the sharp edge location to provide localized fiber density and orientation that enhances strength at this vulnerable point, while the main preform provides the overall structural form.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If movable blocks are used to shape the flanges in the forming tool, then the desired geometry can be approximated, but expensive tooling is required and the rounding occupied by the preform depends on the thickness of the lower plies which can be deformed due to suction

Engineering Contradiction:
Improvegeometry precision of flangesVSAvoidcomplexity of forming tool
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by pre-forming the auxiliary fibrous reinforcement (cord or strand) with the desired sharp edge geometry before placing it in the mold. This preliminary preparation of the reinforcement itself carries the geometric information, eliminating the need for complex movable blocks in the forming tool to shape the flanges during the molding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts the geometric shaping function from the complex forming tool by incorporating it directly into the auxiliary fibrous reinforcement. The cord or strand is pre-formed to the desired shape, and this shape is transferred to the final product during molding, thereby removing the need for expensive and complex movable blocking tooling.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If frayed edges are used to distribute fibers in the junctions between flanges and annular body, then fiber distribution is achieved, but heterogeneity of fiber density reduces the mechanical strength particularly resistance to bending stress

Engineering Contradiction:
Improvefiber distribution in junctionsVSAvoidresistance to bending stress
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The invention applies homogeneity by using an auxiliary fibrous reinforcement in the form of a cord or strand with uniform fiber density and consistent composition. This homogeneous reinforcement is placed at the sharp edge location to ensure uniform fiber distribution and consistent mechanical properties, avoiding the heterogeneity and strength reduction associated with frayed edges.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The invention applies composite materials by combining the main preform material with an auxiliary fibrous reinforcement (cord or strand) to create a composite structure. This composite approach allows the auxiliary reinforcement to specifically address the strength requirements at the sharp edge junction while the main preform provides the overall structural matrix, achieving both good fiber distribution and high bending stress resistance.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2883688B1Composite annular casing of a turbomachine compressor and method for its manufacture
Publication Date: 2021.09.22 SAFRAN AERO BOOSTERS SA
  • EP2883688B1 patent drawingFigure 1~2
  • EP2883688B1 patent drawingFigure 3~4
  • EP2883688B1 patent drawingFigure 5~6

AI summary

A composite annular housing for a low-pressure turbomachine compressor, comprising a generally circular or arcuate wall; a mounting flange extending radially from an edge of the wall, forming an edge with said wall; a primary fiber reinforcement (38) extending continuously along the wall and the flange, forming a bent and rounded portion at the edge; an auxiliary fiber reinforcement (56) extending along the edge; and a matrix. The auxiliary reinforcement (56) includes a core extending along the edge so as to fill the volume between the edge and the bent portion of the primary reinforcement (38). Also included is a turbomachine comprising a composite annular housing, and a method for manufacturing a composite annular housing for a turbomachine.