Fan Case Composite Liner Force Distribution
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Solution Overview
Problem
Conventional fan cases in gas turbine engines are heavy due to metallic shrouds and lack effective noise attenuation and force distribution, which can lead to point loading during blade-off events and increased noise levels.
Innovation Solution
A fan case design featuring an annular outer shroud and a composite liner with a force-distribution band, incorporating honeycomb materials for noise absorption and reinforcing fibers for structural integrity, along with fasteners and washers for secure attachment, to distribute forces and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic shrouds are used in fan cases, then structural strength is improved, but weight increases
Solution Approach 1:
The patent applies composite materials by bonding composite reinforcements to the inner surface of the metallic shroud. This combination allows the structure to maintain the strength benefits of metal while reducing overall weight through the use of lighter composite materials, directly resolving the contradiction between structural strength and weight.
2Strength
If composite reinforcements are coupled by hanger features or adhesives, then structural strength is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex hanger features from the design. By directly bonding composite reinforcements to the shroud inner surface using adhesives only, the design removes the unnecessary intermediate hanger components, thereby reducing device complexity while maintaining structural strength through the adhesive bonding method.
3Ease of manufacture
If conventional fan cases are designed, then manufacturing simplicity is maintained, but noise attenuation is insufficient
Solution Approach 1:
The patent incorporates porous absorptive material within the composite reinforcement structure. This porous material effectively attenuates noise generated by the fan assembly while being integrated into the existing manufacturing process of bonding reinforcements to the shroud, thus maintaining manufacturing simplicity while adding noise attenuation functionality.
4Strength
If metallic shrouds are used, then force distribution during blade-off events is improved, but point loading occurs
Solution Approach 1:
The patent applies local quality by positioning composite reinforcements specifically at the regions where blades contact the shroud during blade-off events. This localized reinforcement distributes the impact forces more evenly across the shroud surface, preventing concentrated point loading while maintaining overall structural strength.
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 provides lightweight structural integrity, effective noise attenuation, and force distribution, preventing point loading and reducing noise levels, while maintaining dynamic stability and allowing for easy repair of components.
Implementation Method 1
The forward damper-filler body may include a honeycomb material having a density lower than a density of the liner-filler body
Implementation Method 2
The inner skin may be bonded to the outer skin adjacent to the front of the fan case to form an axially-forward section of the composite liner and bonded to the outer skin adjacent to the back of the fan case
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fan case (10,210) for use in a gas turbine engine (100) of an aircraft includes an outer shroud and a liner extending along the outer shroud. The fan case (10,210) provides a protective band that blocks fan blades (114) from being thrown out of the fan case (10,210) in case (128) of a blade-off event in which a fan blade (114) is released during operation of the gas turbine engine (100).