Composite Fan Containment Case Fabrication via Segmented Mandrel Wrapping
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Solution Overview
Problem
The existing methods for fabricating composite fan containment cases for gas turbine engines are challenging due to the need for conforming fiber preforms, which are difficult and expensive to produce, often resulting in wrinkles and increased manufacturing costs, especially when using unidirectional tape or woven fabric forms.
Innovation Solution
The method involves forming a core layer material wrapped around cylindrically-shaped spools and mandrels, allowing for the transfer and shaping of the material into a cylindrical fan containment case with a substantially circular cross-sectional area, reducing wrinkle development and manufacturing costs through additional tension and simplified accessory mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conforming fiber preforms are used to match the fan case geometry, then the composite fan case can be fabricated with proper shape, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The manufacturing process is divided into separate stages: first forming the fiber preform on a simple cylindrical mandrel, then wrapping the preformed material around the final fan case geometry. This segmentation allows each stage to use simpler tooling while achieving the complex final shape.
Solution Approach 2:
The fiber preform is formed in advance on a simple cylindrical mandrel before being transferred to the final fan case geometry. This preliminary formation simplifies the tooling requirements and manufacturing complexity while still achieving the desired final shape.
2Shape
If conforming fiber preforms are fabricated to match the fan case shape, then the composite structure can be properly formed, but wrinkles may develop reducing quality
Solution Approach 1:
The forming process is segmented into preformation on a cylindrical mandrel followed by wrapping around the final geometry. This separation allows the fiber layers to be formed without wrinkles on the simple mandrel, then transferred to the complex final shape, maintaining surface quality.
3Strength
If metallic casing shells are used to increase radial and axial stiffness, then engine stress resistance improves, but overall engine weight increases
Solution Approach 1:
The fan containment case is constructed from composite materials (fiber preform with resin matrix) instead of solid metallic casing. This provides the necessary strength and stiffness to resist engine stresses during FOD events while significantly reducing the overall weight compared to metallic alternatives.
Data Source
AI summary
A method of fabricating a fan containment case for a gas turbine engine is provided. The method includes forming a core layer material, wrapping the core layer material about a cylindrically-shaped take-up spool, and transferring the core layer material to a cylindrically-shaped mandrel by wrapping a plurality of layers of the core layer material about the mandrel such that the mandrel is circumscribed by the layers and such that a size and a cylindrical shape of the fan containment case are defined by the layers of core layer material.