Aircraft Nacelle Junction Flange Flex Zone for FBO Energy Absorption
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Solution Overview
Problem
Existing connecting devices for aircraft nacelles face challenges in withstanding the deformation and energy wave caused by fan blade off (FBO) without complicating manufacturing, as additional parts like angle brackets are difficult to implement.
Innovation Solution
A flange design with a groove cut into the joining wing to create a local narrowing of the cross-section, allowing the flange to deform and absorb deformation energy, eliminating the need for additional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional parts like angle brackets are added to the joining flanges to absorb deformation, then the ability to withstand FBO energy wave is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The deformation absorption function is merged into the joining flange itself by integrating a groove directly into its structure. This eliminates the need for separate angle brackets or additional deformation-absorbing components, as the flange now performs both its primary joining function and the secondary function of absorbing deformation energy through its integrated groove feature.
Solution Approach 2:
Instead of adding global structural complexity throughout the entire connection device, the solution applies a localized groove feature at a specific critical location on the joining flange. This local modification creates a controlled deformation zone exactly where needed to absorb the FBO energy wave, without affecting or complicating other parts of the structure.
2Reliability
If additional parts like angle brackets are added to the joining flanges to absorb deformation, then the ability to withstand FBO energy wave is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The deformation absorption function is merged into the joining flange itself by integrating a groove directly into its structure. This eliminates the need for separate angle brackets or additional deformation-absorbing components, as the flange now performs both its primary joining function and the secondary function of absorbing deformation energy through its integrated groove feature.
Solution Approach 2:
Instead of adding global structural complexity throughout the entire connection device, the solution applies a localized groove feature at a specific critical location on the joining flange. This local modification creates a controlled deformation zone exactly where needed to absorb the FBO energy wave, without affecting or complicating other parts of the structure.
3Strength
If the flange cross-section is uniformly strong, then the structural integrity is maintained, but the ability to absorb deformation energy locally is reduced
Solution Approach 1:
The groove creates a localized region of reduced cross-sectional area at a specific position on the joining flange. This local variation in geometry creates a controlled weakness that preferentially deforms first during FBO events, allowing the flange to absorb deformation energy through plastic deformation in this specific zone while the rest of the flange maintains its full strength and structural integrity.
Solution Approach 2:
The groove is pre-formed during manufacturing as a deliberate design feature, creating a predetermined deformation zone that will absorb energy during FBO events. This proactive design element is built in beforehand to cushion the impact of blade-off forces, preventing uncontrolled deformation elsewhere in the structure and protecting the overall integrity of the nacelle connection.
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 flange effectively absorbs deformation energy during FBO, protecting the connection and reducing weight while maintaining structural integrity without additional components.
Implementation Method 1
the local narrowing of the cross-section due to the groove forming a deformation zone of the flange. Thus, it is the flange itself, through its deformation, that prevents the propagation of deformation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a flange for joining an engine compartment (5) to an air intake compartment (4) of an aircraft, comprising a first wing, called base (11), shaped to be placed on an external surface (S) of one of the engine compartment (5) or of the air intake compartment (4), called mounting surface, and a second wing called junction wing (12), comprising at least one passage opening from a connecting element of said junction flange (1) to another flange, inclined relative to the base (11), the junction flange (1) comprising at least one groove (17) cut into the junction wing (12), so as to create a local narrowing of cross-section.