CMC Vane Flange Geometry for Compressive Load Transfer
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in airfoils of gas turbine engines poses challenges due to difficulties in attachment and load distribution, as traditional attachment features for metal alloys are inefficient and not suitable for CMCs, which are sensitive to stress directionality.
Innovation Solution
A CMC vane arc segment with a flange having a sloped radial face that facilitates load transmission along a favorable compression direction, utilizing a flange geometry that is elongated in the circumferential direction and sloped at an angle of 30 to 60 degrees, allowing for efficient load distribution and attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional metal alloy attachment features are used for CMC fairings, then attachment is possible, but the attachment features are inefficient and incompatible with CMC stress directionality sensitivity
Solution Approach 1:
The invention changes the geometric parameters of the attachment feature by introducing a sloped radial face at a specific angle (30-60 degrees) relative to the radial direction. This parameter change creates a favorable stress state that aligns with CMC material properties, resolving the contradiction between manufacturability and stress compatibility
Solution Approach 2:
The sloped radial face creates a localized region with different geometric properties compared to traditional attachment features. This local quality change ensures that stresses are distributed in a direction compatible with CMC fiber orientation, while maintaining overall attachment functionality
2Ease of manufacture
If CMC fairings are designed with traditional attachment features, then manufacturing is simplified, but thermal gradients and stress concentrations occur
Solution Approach 1:
By changing the geometric parameter of the attachment face to a sloped configuration, the invention modifies heat flow paths and stress distribution. This parameter change reduces thermal gradients and stress concentrations while maintaining manufacturing simplicity through fiber ply lay-up techniques
3Strength
If fiber plies are turned up to form flange, then load transmission focuses in compression, but manufacturing complexity increases
Solution Approach 1:
The fiber plies are turned up during the manufacturing process to pre-form the flange structure with the desired sloped radial face. This preliminary action during fabrication simplifies the overall manufacturing process and reduces assembly complexity, while achieving the compressive load transmission benefit
Data Source
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AI summary
A vane arc segment (60) includes a ceramic matrix composite fairing (62) that has first and second platforms (64, 66) and an airfoil section (68) that extends in a radial direction (RD) there between. Each of the first and second platforms (64, 66) includes axially-facing leading and trailing sides (70c, 70d), a core gaspath side (70a), and a non-core gaspath side (70b). The non-core gaspath side (70b) of the first platform (64) has a flange (72) that projects radially there from and extends adjacent the trailing side (70d). The flange (72) has a radial face (72a) that is sloped with respect to the radial direction (RD).