Composite Fan Case Containment System with Internal Grid

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Solution Overview

Problem

Conventional softwall fan containment systems for larger diameter gas turbine engines face challenges in achieving sufficient structural integrity and cost-effective fabrication, as aluminum honeycomb structures may not provide adequate residual stiffness and strength, and bonding processes are costly.

Innovation Solution

A cylindrical composite fan case structure with an internal and external grid pattern formed by reinforcing fiber windings in a resin matrix, where the internal grid acts as a damage-limiting substructure and the external grid provides additional strength and stiffness, potentially eliminating the need for dry containment fabric.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum honeycomb structures are used in softwall containment systems, then weight is reduced, but structural integrity (residual stiffness and strength) is insufficient

Engineering Contradiction:

ImproveweightVSAvoidstructural integrity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The patent replaces conventional aluminum honeycomb structures with a composite lattice structure made of fiber-reinforced materials. This composite lattice provides both the weight reduction benefits of softwall systems and the structural integrity needed to contain fan blade fragments, resolving the contradiction between lightweight design and structural strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent implements varying ply orientations and material properties at different locations within the lattice structure. Specific regions have enhanced structural properties to handle localized impact loads from blade fragments, while other regions maintain lower weight, thus achieving both weight reduction and structural integrity.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If bonding net shape aluminum honeycomb to composite inner shell is performed, then structural assembly is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvefabrication processVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent combines the lattice structure and containment shell into a single integrated composite structure manufactured in one piece using automated fiber placement. This eliminates the need for separate bonding operations between lattice and shell, reducing both manufacturing complexity and cost while maintaining structural integrity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite lattice structure is manufactured to net shape using automated processes that lay down fibers and cure resin in a single operation. The structure serves its own structural and containment functions without requiring additional assembly steps or bonding materials, reducing manufacturing cost.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8986797B2Fan case containment system and method of fabrication

Publication Date: 2015.03.24 GENERAL ELECTRIC CO

AI summary

Composite article includes a generally cylindrical body having an internal grid structure interleaved with casing layers formed of reinforcing fibers disposed in a resin matrix. The composite article may be utilized in a fan case containment system for aircraft engine applications. Methods for fabricating the composite article are also provided.