Fan Containment Assembly With Crushable Impact Structure
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Solution Overview
Problem
Existing containment assemblies for gas turbine engines are susceptible to being cut by metallic fan blade material during a fan-blade-off event, rather than being crushed, due to insufficient compressive strength and material properties, which can lead to ineffective containment and potential forward ejection of fan blade fragments.
Innovation Solution
A containment assembly with an outer and inner impact structure having different compressive strengths and discontinuous profiles between the forward and fan portions, reducing compressive strength in the fan portion to facilitate capture and arrest of fan blade material, thereby preventing forward ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impact structure has high compressive strength to resist cutting by metallic fan blade material, then the containment effectiveness is improved, but the ability to absorb impact energy through crushing is reduced
Solution Approach 1:
The impact structure is divided into multiple discrete elements or cells arranged in a honeycomb or cellular pattern. Each cell can crush independently, providing both energy absorption through crushing and resistance to cutting forces, as the segmented structure prevents propagation of cuts across the entire impact structure.
Solution Approach 2:
The impact structure employs composite material construction, combining materials with different properties - such as a face sheet of high impact-resistant material that resists denting and cutting, with a core material that provides energy absorption through crushing. This composite approach allows simultaneous achievement of cutting resistance and energy absorption.
2Stability of the object's composition
If the impact structure has uniform compressive strength throughout, then structural integrity is maintained, but the ability to locally adapt to fan blade impact is reduced
Solution Approach 1:
The impact structure features non-uniform cell density or material properties distributed across its surface. Regions with higher cell density or stronger material are positioned to handle expected impact zones, while other regions have lower density for optimized energy absorption. This local variation allows the structure to adapt to fan blade impact characteristics while maintaining overall structural integrity.
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
The design effectively captures and arrests fan blade material during a failure event, preventing forward ejection and ensuring the material is ingested by the engine or bypass flow, enhancing safety and containment efficiency.
Implementation Method 1
the honeycomb impact structure, which is compressed and/or crushed as it absorbs the energy of the impacting blade
Implementation Method 2
compressed and/or crushed as it absorbs the energy of the impacting blade
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
There is disclosed a containment assembly (500 for a gas turbine engine, comprising: an outer impact structure (56); an inner impact structure (54) disposed radially within the outer impact structure; wherein the outer impact structure and the inner impact structure axially extend between a fan portion (4) of the containment assembly corresponding to an axial location of a fan and a forward portion (2) of the containment assembly axially forward of the fan portion; and wherein at least one of the outer impact structure and the inner impact structure has a discontinuous profile between the forward portion and the fan portion so that there is a local reduction in compressive strength in the fan portion.