Gas Turbine Fan Case Composite Ballistic Liner Design

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Solution Overview

Problem

Gas turbine engine fan cases face challenges in balancing blade containment with the need for low weight and high strength, particularly in preventing fan blade fragments from exiting the engine while maintaining structural integrity.

Innovation Solution

A composite fan case structure utilizing unidirectional roving fiber layers and non-crimp fabric layers, combined with a fiberglass layer and an inner ballistic liner, provides a lightweight and efficient containment system, with the ballistic liner resisting ballistic threats and the composite structure replacing traditional metal alloys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional metal alloy fan case is used to contain fan blade fragments, then blade containment capability is improved, but weight increases and strength-to-weight ratio deteriorates

Engineering Contradiction:
Improveblade containment capabilityVSAvoidfan case weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The fan case employs a composite structure consisting of a metal alloy outer case and a composite ballistic liner. The ballistic liner is constructed from multiple layers including unidirectional roving fiber layers, non-crimp fabric layers, and a fiberglass layer, combined with an inner ballistic liner. This composite material system provides superior blade containment capability while reducing overall weight compared to traditional solid metal alloy cases.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The ballistic liner is nested within the metal alloy outer case, creating a multi-layered containment system. The unidirectional roving fiber layers, non-crimp fabric layers, fiberglass layer, and inner ballistic liner are arranged in concentric layers, with each layer providing specific functional properties for blade fragment containment while optimizing the weight-strength relationship.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If the fan case structure is strengthened to prevent blade fragments from exiting, then blade containment is improved, but structural weight increases

Engineering Contradiction:
Improvecontainment strengthVSAvoidfan case weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The composite ballistic liner provides high containment strength through the synergistic combination of unidirectional roving fibers (providing tensile strength), non-crimp fabric layers (providing multidirectional reinforcement), fiberglass layer (providing structural integrity), and inner ballistic liner (providing impact resistance). This composite system achieves superior strength-to-weight ratio compared to traditional metal alloy structures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The ballistic liner is strategically positioned in the region where blade fragment impact is most likely to occur, providing localized high-strength containment exactly where needed. The multi-layer composite structure concentrates reinforcement in the critical containment zone rather than uniformly strengthening the entire fan case, thereby optimizing strength distribution and minimizing unnecessary weight.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2815084B1Gas turbine case with ballistic liner
Publication Date: 2020.07.29 RTX CORP
  • EP2815084B1 patent drawingFigure 1
  • EP2815084B1 patent drawingFigure 2
  • EP2815084B1 patent drawingFigure 3~5

AI summary

A case for a gas turbine engine includes a containment section with a plurality of unidirectional roving fiber layers and a plurality of non-crimp fabric layers. A method of manufacturing the case includes winding the plurality of unidirectional roving fiber layers around the plurality of non-crimp fabric layers.