CMC Vane Ring Attachment for Low-Stress Turbine Support

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Solution Overview

Problem

Challenges exist in attaching ceramic matrix composite (CMC) airfoils in gas turbine engines due to stress directionality, manufacturing limitations, and sealing requirements, which traditional attachment features for metal alloys are inefficient or unattainable.

Innovation Solution

A ring-strut-ring configuration using full hoop ceramic support rings and elongated platform flanges constrains ceramic vane arc segments, providing efficient loading and reducing stress concentrations through a 'cross-corner' loading scheme, with additional features like anti-rotation tabs and load pads to manage movement and stress separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional attachment features for metal alloys are used to attach ceramic matrix composite (CMC) airfoils, then the attachment method is familiar and easy to implement, but the attachment is inefficient and creates stress concentrations due to stress directionality and manufacturing limitations of CMC

Engineering Contradiction:

Improveease of attachment implementationVSAvoidattachment efficiency and stress distribution

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The CMC airfoil is divided into multiple arc segments that can be attached separately to the support rings. This segmentation allows for simplified attachment of individual segments while distributing stress across multiple interfaces, resolving the contradiction between ease of manufacture and attachment reliability for CMC materials

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A bonding adhesive is introduced as an intermediary between the CMC airfoil segments and the support rings. This adhesive layer accommodates the stress directionality constraints of CMC while providing reliable attachment, eliminating stress concentrations that would occur with direct mechanical attachment methods designed for metal alloys

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If CMC materials are used for airfoils, then high temperature resistance is improved, but unique challenges arise in attachment due to stress directionality and manufacturing limitations

Engineering Contradiction:

Improvetemperature resistanceVSAvoidattachment configuration complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The attachment configuration transitions from traditional in-plane mechanical features to a three-dimensional ring-strut-ring arrangement with elongated platform flanges. This dimensional change allows the attachment to accommodate CMC stress directionality constraints while maintaining structural integrity at high temperatures

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The attachment design changes key geometric parameters including the elongation of platform flanges in the circumferential direction and the positioning of load pads at specific locations on the airfoil platforms. These parameter changes optimize stress distribution for CMC materials under high temperature conditions

Inventive Principle:

Principle #35Parameter changes

3Strength

If ceramic vane arc segments are constrained by support rings, then structural integrity and deflection resistance are improved, but additional features like anti-rotation tabs and load pads increase manufacturing complexity

Engineering Contradiction:

Improvestructural integrity and deflection resistanceVSAvoidmanufacturing complexity of attachment features

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Multiple attachment features including platform flanges, load pads, and anti-rotation tabs are merged into a unified ring-strut-ring configuration. This integration achieves comprehensive constraint of the CMC airfoil segments while simplifying the manufacturing process compared to adding separate features

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12523157B2Ceramic vane ring-strut-ring attachment configuration

Publication Date: 2026.01.13 RTX CORP

AI summary

A gas turbine engine includes a turbine section that has inner and outer diameter full hoop ceramic support rings that define an annulus there between and ceramic vane arc segments disposed in the annulus. Each segment has radially outer and inner platforms and an airfoil section. The radially outer platform includes an outer platform flange. The radially outer full hoop ceramic support ring axially constrains each of the ceramic vane arc segments via the outer platform flanges, and the radially outer diameter full hoop ceramic support ring radially constrains each of the ceramic vane arc segments at a location adjacent an axially-facing trailing side of the radially outer platform. The radially inner diameter full hoop ceramic support ring radially constrains each of the ceramic vane arc segments at a location adjacent the axially-facing leading side of the radially inner platform.