Al-Li Composite Airfoil Braided Fabric Weight Reduction
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Solution Overview
Problem
Current compressor airfoils for gas turbine engines are heavy, expensive to manufacture, and lack the necessary strength and durability for land-based operations, with existing metal matrix composite solutions either too costly or insufficiently strong for high-stress applications.
Innovation Solution
A lightweight metal matrix composite airfoil featuring a braided fabric of twisted fiber tows embedded in an aluminum-lithium alloy, where the alloy penetrates the interstices of the fabric to form a continuous outer surface, providing enhanced strength and reduced weight, and is manufactured using methods like precision mold casting and pressure-augmented die casting to optimize production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional steel and iron-base alloy parts are used for compressor airfoils, then sufficient strength and durability are achieved, but weight is excessive
Solution Approach 1:
The patent uses a metal matrix composite consisting of an aluminum-lithium alloy matrix combined with a braided fabric reinforcement structure. This composite material approach allows weight reduction compared to traditional steel airfoils while maintaining sufficient strength through the synergistic combination of lightweight metal and fibrous reinforcement.
Solution Approach 2:
The braided fabric is strategically positioned within the aluminum-lithium alloy matrix at locations where additional strength is needed. The fabric tows are oriented at specific angles relative to the airfoil geometry to provide localized reinforcement in high-stress areas, optimizing the strength-to-weight ratio.
2Weight of moving object
If fiber composite blades are used to reduce weight, then weight is reduced, but manufacturing cost increases and scrap rate increases
Solution Approach 1:
The patent employs an aluminum-lithium alloy matrix that can be processed using established metal casting techniques rather than requiring complex composite manufacturing processes. By changing the base material from traditional steel or polymer composites to a metal matrix with fabric reinforcement, the manufacturing process becomes more straightforward with lower scrap rates while achieving weight reduction.
3Weight of moving object
If metal matrix composite components are used, then weight is reduced, but manufacturing cost increases
Solution Approach 1:
The composite structure is segmented into distinct components: the aluminum-lithium alloy matrix and the braided fabric reinforcement. This segmentation allows each component to be manufactured separately using optimized processes, then combined through infiltration, reducing overall manufacturing complexity and cost compared to monolithic composite structures.
Solution Approach 2:
A polymer matrix is used as an intermediary during the manufacturing process to facilitate the infiltration of aluminum-lithium alloy into the braided fabric structure. The polymer serves as a temporary matrix that enables proper impregnation and consolidation, then is removed or degraded, allowing the final metal-fabric composite to form without requiring complex direct metal processing.
4Weight of moving object
If hollow airfoils are produced to reduce weight, then weight is reduced, but structural integrity and strength are compromised
Solution Approach 1:
The patent creates a composite structure where the aluminum-lithium alloy matrix provides a continuous, strong base material that maintains structural integrity, while the embedded braided fabric tows provide additional reinforcement. This composite approach avoids the weakness of hollow structures by maintaining material continuity throughout the airfoil section.
Solution Approach 2:
The braided fabric reinforcement is strategically placed within the aluminum-lithium alloy matrix at locations where additional structural support is needed. This localized reinforcement approach maintains overall structural integrity while minimizing weight compared to uniform thickening or hollow designs.
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 achieves significant weight reduction while maintaining sufficient strength and durability for high-stress compressor blade applications, offering improved efficiency and reduced manufacturing costs, with the braided fabric design enhancing structural integrity and the aluminum-lithium alloy ensuring a robust yet lightweight construction.
Implementation Method 1
The aluminum-lithium alloy penetrates the interstices of the braided fabric and the plurality of twisted fiber tows to form an outer surface of aluminum lithium alloy
Data Source
AI summary
A metal matrix composite lightweight compressor airfoil. The airfoil comprises a braided fabric embedded in a lightweight aluminum-lithium alloy. The airfoils are fabricated by forming a plurality of fiber tows by twisting filaments or fibers. The tows are then braided into a fabric. The fabric may be impregnated with an optional fugitive polymer that temporarily occupies interstices of the fabric to facilitate handling of the pre-formed braided fabric, but which is subsequently removed. The airfoil may then be formed as a MMC by one of two separate methods. In the first method, aluminum-lithium alloy is pressure augmented casting into a die that includes a preform of fabric impregnated with fugitive polymer. In a second method, a preform is formed using a tool and mandrel by impregnating fabric with aluminum-lithium alloy. Then aluminum-lithium alloy is pressure augmented cast into a die that includes the alloy-impregnated preform.