Layered Turbofan Blade Containment Arrangement
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Solution Overview
Problem
Turbofan gas turbine engine blade containment arrangements face challenges in withstanding ice impacts, accommodating radial variations and vibrations, and maintaining the trajectory of detached fan blades during failures, while also aiming to reduce weight and maintain structural integrity.
Innovation Solution
A layered containment arrangement comprising a first and second layer of cellular material, a strong and ductile layer with chopped glass fibers, and an abradable layer, where the cellular materials can be honeycomb or foam, and the strong and ductile layer is designed to absorb energy from impacts without rupturing, allowing for efficient energy absorption and distribution across the containment system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic fan casing with thicker regions is used to contain detached fan blades, then the containment strength is improved, but the weight of the fan casing increases
Solution Approach 1:
The patent employs a composite containment arrangement consisting of multiple material layers including cellular material (honeycomb or foam), strong and ductile material with chopped glass fibres, and abradable material. This composite structure achieves the required containment strength while reducing overall weight compared to solid metallic casings, as each layer contributes specific properties (energy absorption, structural strength, adaptability) without requiring excessive thickness throughout.
Solution Approach 2:
The containment arrangement uses different materials with specific properties positioned at different radial locations to address local requirements. The cellular material provides initial energy absorption, the strong and ductile layer with chopped glass fibres provides structural integrity and blade containment, and the abradable layer accommodates radial variations. This localized material distribution optimizes strength where needed while minimizing unnecessary weight in other areas.
2Strength
If the fan blade containment arrangement is made stronger to withstand ice impacts, then the impact resistance is improved, but the ability to accommodate radial position variation and vibrations deteriorates
Solution Approach 1:
The containment arrangement assigns different functional properties to different material layers at different locations. The abradable material layer is specifically positioned to accommodate radial position variations and vibrations through its compliant nature, while the strong and ductile layer with chopped glass fibres provides impact resistance. This spatial differentiation of material properties allows simultaneous achievement of impact resistance and adaptability without compromise.
Solution Approach 2:
The multi-material composite structure enables dissociation of functions: the cellular material and strong and ductile layer handle impact forces, while the abradable material layer handles radial variations and vibrations. This functional separation within the composite system allows each layer to optimize its performance for its specific purpose without interfering with the other requirements.
3Weight of stationary object
If the fan blade containment arrangement is made thinner to reduce weight, then the weight is reduced, but the ability to contain detached fan blades deteriorates
Solution Approach 1:
The patent uses a composite structure with multiple functional layers that together provide adequate blade containment capability at reduced thickness. The cellular material layer absorbs impact energy, the strong and ductile layer with chopped glass fibres provides structural containment strength, and the abradable layer ensures adaptability. This composite approach achieves containment performance comparable to or exceeding solid metallic structures while significantly reducing weight due to the lower density and optimized thickness of each layer.
Solution Approach 2:
The containment arrangement is segmented into multiple functional layers, each contributing to the overall containment capability. This segmentation allows the system to achieve the required containment performance through the combined effect of multiple thinner layers rather than requiring a single thick metallic structure, thereby reducing overall weight while maintaining or improving containment effectiveness.
4Loss of energy
If a layered containment arrangement with multiple materials is used to reduce weight and improve energy absorption, then the weight is reduced and energy absorption is improved, but the structural complexity increases
Solution Approach 1:
The containment arrangement is divided into distinct functional layers (cellular material, strong and ductile material with chopped glass fibres, abradable material), where each layer is optimized for a specific function. This segmentation enables weight reduction and improved energy absorption by using lightweight materials in non-critical areas while maintaining structural integrity. The modular layered structure, while appearing complex, simplifies manufacturing and assembly compared to monolithic designs, as each layer can be independently selected and installed based on its specific function.
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 solution effectively absorbs and distributes the energy from fan blade impacts, preventing penetration through the containment arrangement, reduces the weight of the fan casing, and maintains the structural integrity necessary to withstand ice impacts and vibrations, while allowing for reduced weight and independent operation from the fan casing design.
Implementation Method 1
a first layer of cellular material, a septum layer arranged within the first layer of cellular material, a second layer of cellular material arranged within the septum layer
Implementation Method 2
the strong and ductile layer is designed to absorb energy from impacts without rupturing
Implementation Method 3
the strong and ductile layer is designed to absorb energy from impacts without rupturing
Implementation Method 4
The strong and ductile layer may comprise chopped fibres in a resin. The strong and ductile layer may comprise chopped glass fibres
Implementation Method 5
a layer of abradable material arranged within the strong and ductile layer
Data Source
Figure 1~2
Figure 3~5
AI summary
A gas turbine engine blade containment arrangement (32) comprises a casing (30), a first layer of cellular material (36) arranged within the casing (30), a septum layer (38) within the first layer of cellular material (36), a second layer of cellular material (40) within the septum layer (38), a strong and ductile layer (42) within the second layer of cellular material (40) and a layer of abradable material (44) within the strong and ductile layer (42).