Impregnation Mandrel Clamping Wedge for Composite Winding

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Solution Overview

Problem

The existing methods for producing composite material fan retention casings for gas turbines face challenges in maintaining the fiber preform during winding on the mandrel, particularly in applying sufficient tensile force without damaging the preform, and ensuring the attachment is harmless during resin impregnation.

Innovation Solution

A mechanical attachment device using a removable plate with a clamping wedge and screws to hold the free end of the fibrous texture on the mandrel by pinching, allowing high winding tension without damaging the preform and being removable for resin impregnation, ensuring the attachment is chemical-free and harmless.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a removable plate with points is used to attach the first layer of fibrous texture, then the attachment is effective, but the tips of the plate may damage the fibrous preform if too high winding tension is applied

Engineering Contradiction:

Improveattachment strengthVSAvoidpreform damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A clamping wedge is introduced as an intermediary element between the removable plate and the fibrous preform. The wedge distributes the clamping force across a broader area of the preform, preventing localized damage from direct point contact while maintaining secure attachment during winding operations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The attachment mechanism transitions from direct point contact (removable plate points) to distributed surface contact (clamping wedge). This changes the stress distribution parameter, reducing peak stresses on the preform while maintaining sufficient attachment strength for high winding tension applications

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a removable plate is used to attach the first layer, then the attachment can be removed before impregnation, but chemical attachment methods may degrade the preform during hot polymerization

Engineering Contradiction:

Improveremovability for impregnationVSAvoidpreform degradation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention replaces chemical attachment methods with a purely mechanical clamping system. The removable plate with clamping wedge provides mechanical attachment that can be easily removed before resin impregnation, avoiding any chemical interaction that might degrade the preform during hot polymerization processes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If high winding tension is applied to ensure effective compacting of fibrous layers, then the preform density is improved, but the preform may be damaged by conventional attachment methods

Engineering Contradiction:

Improvepreform densityVSAvoidpreform integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The clamping wedge changes the stress distribution parameter by distributing the clamping force across a broader area of the preform. This allows high winding tension to be applied for effective compacting and density improvement while preventing localized stress concentrations that would damage the preform structure

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

This solution enables secure attachment of the first layer of fibrous texture without risk of damage, allowing high winding tension and ensuring the preform's integrity during resin impregnation, thereby facilitating the production of composite material gas turbine casings with improved reliability and safety.

Implementation Method 1

The device for holding by pinching also comprises a clamping wedge capable of exerting a clamping force on the free end of the layer of fibrous texture wound on the mandrel

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP2771173B1Impregnation mandrel comprising a clamping system for the production of gas turbine casings from composite material

Publication Date: 2018.01.10 SAFRAN AIRCRAFT ENGINES SAS

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AI summary

The invention relates to an impregnation mandrel (100) for the production of gas turbine casings made from composite material, said mandrel comprising: an annular wall (102), in which the profile of the outer surface corresponds to that of the internal surface of the casing to be produced; two side plates (104), the profiles of which correspond to those of external casing flanges to be produced; and a removable device (106) for clamping a layer having a fibrous texture, which is wound around the mandrel.