Tethered Composite Flange Corners for Bridging Prevention

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Solution Overview

Problem

Current flange lay-up processes for composite materials face challenges such as bridging, where the initial fabric ply pulls away from the flange corner, leading to resin richness and local weakening of the laminate, due to inadequate placement, bulk removal, and thermal expansion differences, with no effective method to monitor and prevent this issue.

Innovation Solution

The implementation of tethered flange corners comprising at least one ply of barrier fibers with a fiber tow wrapped around them, along with additional plies of filler and flange fibers, helps secure the barrier fibers in place during lay-up and cure, using multidirectional textile preforms and tackification with resin to maintain adherence and prevent bridging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fabric plies are repeatedly applied to build up the flange, then the flange achieves desired dimensions, but the initial fabric ply cannot be monitored and may bridge away from the corner

Engineering Contradiction:

Improvefabric ply placement accuracyVSAvoidfabric layup process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The corner is prepared in advance by applying a release agent to the tooling corner before placing the first fabric ply. This preliminary action creates a controlled interface that prevents bridging while allowing subsequent plies to be applied without monitoring the initial ply placement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A release agent serves as an intermediary substance between the tooling corner and the fabric ply. This intermediary controls the adhesion characteristics, allowing the fabric to be placed accurately at the corner without requiring continuous monitoring during the layup process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If fabric plies are inadequately placed or bulk is not removed, then the layup process is faster, but bridging occurs during curing

Engineering Contradiction:

Improvelayup process speedVSAvoidfabric adhesion reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The corner region is pre-treated with release agent and prepared as a specific zone before the main layup begins. This preliminary preparation ensures that even if subsequent plies are applied quickly without careful monitoring, the corner fabric remains securely in place and does not bridge.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The corner region receives special treatment with release agent application, creating a localized zone with different adhesion characteristics than the rest of the flange. This local quality enhancement ensures reliable fabric adhesion at the critical corner area while allowing faster processing elsewhere.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If fabric plies are terminated at the corner to allow slippage, then thermal expansion differences are addressed, but bridging from jostling or inadequate bulk removal cannot be prevented

Engineering Contradiction:

Improvethermal expansion mismatchVSAvoidfabric adhesion during curing

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The release agent acts as an intermediary that provides controlled slippage to accommodate thermal expansion differences between the tooling and fabric during curing. Simultaneously, it maintains sufficient adhesion to prevent bridging caused by jostling or inadequate bulk removal, solving both problems with a single mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 tethered corner design effectively reduces or eliminates bridging by maintaining the barrier fibers' position during lay-up and cure, enhancing the adhesion and structural integrity of the composite flange by preventing resin accumulation and addressing thermal expansion issues.

Implementation Method 1

at least one fiber tow wrapped about the barrier fibers

Methodology Applied

Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

tackification with resin to maintain adherence

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS7749927B2Tethered corners and flanges and articles comprising the same

Publication Date: 2010.07.06 GENERAL ELECTRIC CO

AI summary

Tethered flange corners including at least one ply of barrier fibers and at least one fiber tow wrapped about the barrier fibers. Also included are flanges having a tethered corner containing at least one ply of barrier fibers, at least one fiber tow wrapped about the barrier fibers, at least one ply of filler fibers applied over the fiber tow, and at least one ply of flange fibers applied over the filler fibers. Additionally included are articles incorporating a composite structure having a flange with a tethered corner containing at least one ply of barrier fibers and at least one fiber tow wrapped about the barrier fibers.