Radial Integral Build-Up Composite Fan Case Attachment

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Solution Overview

Problem

Existing composite fan cases for gas turbine engines face challenges in attaching components due to bonded features being liberated during high-energy events and threaded fasteners degrading the structural capability of the containment case.

Innovation Solution

A composite fan case design featuring radially stacked composite plies interleaved with wound layers to form radial integral build-ups, which include machined recesses for threaded metallic holes, providing customized attachment points and local reinforcement without secondary bonding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If threaded fasteners are used to attach components to the composite fan case, then attachment capability is provided, but the structural capability of the containment case is degraded

Engineering Contradiction:

Improveattachment capabilityVSAvoidstructural capability

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent implements local reinforcement by stacking additional composite plies at specific radial locations where attachment hardware is needed. This creates localized build-ups that provide structural support exactly where fasteners are required, rather than uniformly thickening the entire case. The localized nature of this reinforcement maintains overall structural capability while enabling attachment points.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The attachment features are integrated into the composite case during the manufacturing process itself, before the case is put into service. The radial build-ups and embedded attachment hardware are formed as part of the laminate stacking sequence, eliminating the need for post-manufacturing modifications and ensuring the structural integrity is maintained from the outset.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If bonded features are used to attach components to the composite fan case, then attachment capability is provided, but the features are liberated during high-energy events

Engineering Contradiction:

Improveattachment capabilityVSAvoidattachment reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent merges the attachment hardware with the composite case structure by embedding fasteners and attachment features directly into the laminate during manufacturing. This integration eliminates separate bonded features that could fail independently, creating a unified structure where the attachment hardware becomes an integral part of the case itself, improving reliability during high-energy events.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes composite material properties by stacking plies in specific orientations and configurations to create radial build-ups that provide both structural support and attachment functionality. The composite laminate structure allows for tailored mechanical properties at attachment locations, ensuring reliable bonding and integration with the overall case structure.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If radial integral build-ups are created by stacking discrete plies, then customized attachment points are achieved, but manufacturing complexity increases

Engineering Contradiction:

Improvecustomized attachment pointsVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the composite case construction into discrete plies that are stacked in a controlled sequence. Each ply can be positioned to contribute to radial build-ups at specific locations, allowing customized attachment points to be created by simply adjusting the stacking sequence rather than requiring complex tooling or post-processing operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The radial integral build-ups serve multiple functions: they provide structural reinforcement at attachment locations, create localized thickness variations for hardware integration, and maintain the overall structural integrity of the composite case. This multi-functionality reduces the need for separate components and simplifies the overall manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design enhances structural integrity by eliminating adhesive bond lines that can fail during high-energy events, reduces manufacturing time and weight, and allows for optimized attachment points without common, oversized details.

Implementation Method 1

a plurality of wound layers that form a laminate... the plurality of radially stacked composite plies interleaved with the wound layers

Methodology Applied

Scientific EffectLamination: Lamination

Data Source

PatentUS10935046B2Integrally built up composite fan case

Publication Date: 2021.03.02 RTX CORP

AI summary

A gas turbine engine fan case may comprise a plurality of wound layers that form a laminate and have a nominal radial fan case thickness, where the laminate includes a plurality of discrete fan case radial locations comprising a plurality of radially stacked composite plies that form a radial integral build up in comparison to the nominal radial fan case thickness.