Ceramic Matrix Composite Blade Track Mounting System

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Solution Overview

Problem

Coupling ceramic matrix composite materials with traditional fasteners in gas turbine engines is challenging due to thermal expansion and material properties, leading to issues with load distribution and stress concentration.

Innovation Solution

A turbine shroud segment with a metallic carrier and ceramic matrix composite blade track, utilizing a mounting system with braces and threaded shafts, track-location arms, and load-reaction arms to distribute and manage pressure loads, preventing bending moments and reducing stress concentration in the ceramic matrix composite material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional fasteners such as rivets or bolts are used to couple ceramic matrix composite components, then the components can be assembled, but thermal expansion and material property differences cause load distribution issues and stress concentration

Engineering Contradiction:
Improveassembly capabilityVSAvoidload distribution and stress concentration
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mounting system is divided into multiple functional components: brackets with engagement features, threaded shafts for secure attachment, track-location arms for positioning, and load-reaction arms for force distribution. This segmentation allows each component to address specific aspects of the coupling problem, improving both assembly capability and load distribution while reducing stress concentration on the ceramic matrix composite material.

Inventive Principle:
Principle #1Segmentation

2Temperature

If ceramic matrix composite materials are used in high temperature turbine shrouds, then temperature resistance is improved, but coupling with metallic carriers becomes difficult due to thermal expansion and material property differences

Engineering Contradiction:
Improvetemperature resistanceVSAvoidcoupling difficulty
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The mounting system acts as an intermediary between the ceramic matrix composite blade track and the metallic carrier. The brackets, threaded shafts, and arms create a transition interface that accommodates the different thermal expansion properties and material characteristics of ceramic and metal, enabling reliable coupling while maintaining the temperature resistance benefits of the ceramic material.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If pressure is applied to push the blade track segment radially inward during use, then the blade track performs its function, but reaction loads are induced that can cause stress concentration

Engineering Contradiction:
Improvefunctional performanceVSAvoidstress concentration resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The load-reaction arms are specifically designed to counterbalance the reaction loads induced when pressure pushes the blade track radially inward. These arms distribute the opposing forces to the metallic carrier through the threaded shafts, preventing stress concentration at critical points on the ceramic blade track segment and maintaining its strength during operational loading.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Data Source

PatentEP3467270B1Ceramic matrix composite blade track with mounting system having reaction load distribution features
Publication Date: 2022.01.19 ROLLS ROYCE CORP
  • EP3467270B1 patent drawingFigure 1~2
  • EP3467270B1 patent drawingFigure 3~4
  • EP3467270B1 patent drawingFigure 5

AI summary

An assembly adapted for use in a gas turbine engine (10) has a carrier (24) component and a supported component. The assembly includes a mounting system (28) for coupling the supported component to the carrier (24) component. In an illustrative embodiment, the assembly is a turbine shroud segment (22) for blocking gasses from passing over turbine blades included in the gas turbine engine.