Interleaved Fiber Layers in Gas Turbine Fan Case
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Solution Overview
Problem
Fan containment cases in gas turbine engines face challenges in effectively containing fan blades during a blade release event, particularly in providing a lightweight yet robust structure that can distribute and absorb the impact of a released blade while minimizing delamination and load concentrations.
Innovation Solution
The design incorporates an annular liner with aramid fiber layers and an annular case body with alternating carbon fiber layers, each with distinct fiber architectures and orientations, interleaved in a specific pattern to enhance load distribution and containment performance, and a method of fabricating this structure by simultaneously wrapping the fiber layers around a mandrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a composite fan containment case is used, then weight is reduced compared to metallic designs, but structural complexity increases to achieve adequate containment performance
Solution Approach 1:
The fan containment case is segmented into multiple thin fiber layers with different architectures (unidirectional, biaxial, triaxial) arranged in a sequence. Each layer provides specific mechanical properties, and the segmented structure allows for optimized weight distribution while maintaining containment performance without requiring a monolithic complex structure.
Solution Approach 2:
The patent employs composite fiber materials with varying architectures (unidirectional, biaxial, triaxial) to create a multi-layered containment case. These composite materials provide high strength-to-weight ratios, enabling weight reduction compared to metallic designs while achieving the required structural performance through material selection rather than increased geometric complexity.
2Reliability
If fiber layers are interleaved with different architectures, then load distribution and containment performance are improved, but manufacturing complexity increases
Solution Approach 1:
The fiber reinforcement is segmented into discrete layers with different architectures (unidirectional, biaxial, triaxial) that are interleaved in a specific sequence. This segmentation allows each layer to address specific load paths and stress states, improving containment performance while enabling modular manufacturing approaches where layers can be prepared and applied systematically.
Solution Approach 2:
Different fiber architectures are placed at different locations through the wall thickness to address local stress requirements. Unidirectional layers handle axial loads, biaxial layers handle combined stresses, and triaxial layers provide comprehensive reinforcement. This local quality approach optimizes containment performance at each location without requiring uniform complex manufacturing throughout the entire structure.
3Strength
If multiple fiber layers with different architectures are used, then impact resistance and delamination resistance are improved, but the number of materials and processing steps increases
Solution Approach 1:
The impact resistance is achieved through segmented fiber layers that are sequentially arranged to progressively absorb and distribute impact energy. The different architectures (unidirectional, biaxial, triaxial) create a layered defense system where each layer contributes to delamination resistance, improving impact performance without requiring a single overly complex material system.
Solution Approach 2:
Composite materials with different fiber architectures are combined to create a multi-functional containment case. The unidirectional layers provide axial strength, biaxial layers add transverse reinforcement, and triaxial layers provide comprehensive impact resistance. This composite approach achieves superior impact resistance while maintaining manufacturing feasibility through the use of established composite fabrication techniques.
Data Source
AI summary
A fan case for a gas turbine engine includes an annular liner and an annular case body. The liner has a plurality of liner fiber layers. The case body surrounds the liner. The case body includes a plurality of first and second fiber layers. The first fiber layers extend axially beyond the second fiber layers in axially forward and aft directions and the second fiber layers are interleaved with the first fiber layers. The first fiber layers each have a first fiber architecture and the second fiber layers each have a second, different fiber architecture.