Ceramic Matrix Composite Roller Joint for Thermal Growth Mismatch

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Solution Overview

Problem

The challenge in gas turbine engines is accommodating the different thermal growth rates between ceramic and metallic materials, which can lead to structural mismatch and stress due to their varying coefficients of thermal expansion, particularly in high-temperature applications.

Innovation Solution

The implementation of a roller joint system that includes a roller race on either the ceramic airfoil or metallic support carrier, with rolling elements that allow for radial movement to accommodate thermal growth disparities, ensuring secure engagement and load transfer between ceramic and metallic components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ceramic materials are used in gas turbine engines to endure high temperatures, then temperature resistance is improved, but thermal growth mismatch occurs between ceramic and metallic components

Engineering Contradiction:

Improvetemperature resistanceVSAvoidthermal growth mismatch

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The roller joint introduces a dynamic mechanism that allows relative movement between the ceramic airfoil and metallic support carrier. The roller elements can move radially to accommodate thermal growth differences while maintaining load transfer, transforming a static rigid connection into a dynamic adaptive connection that resolves the thermal expansion mismatch problem

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The roller joint acts as an intermediary mechanism between the ceramic airfoil and metallic support carrier. It mediates the thermal growth mismatch by providing a controlled interface that allows differential expansion while maintaining structural integrity and load transfer capability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If a rigid connection is used between ceramic airfoil and metallic support carrier, then structural integrity is maintained, but thermal expansion differences cause stress and potential failure

Engineering Contradiction:

Improvestructural integrityVSAvoidstress from thermal mismatch

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The roller joint creates a dynamic connection that maintains structural integrity through controlled rolling contact. The roller elements transfer loads while allowing radial movement, ensuring the connection remains strong during operation while accommodating thermal expansion differences that would otherwise cause stress

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The roller joint changes the operational parameters of the connection by introducing radial movement capability. This parameter change allows the connection to adapt to thermal expansion variations, maintaining reliability under different thermal conditions while preserving structural integrity

Inventive Principle:

Principle #35Parameter changes

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

This solution effectively mitigates the thermal growth mismatch by enabling relative radial movement, maintaining structural integrity and supporting the ceramic airfoils while managing thermal expansion differences, thus enhancing the durability and performance of gas turbine components.

Implementation Method 1

accommodate radial thermal growth disparity

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

roller joint for supporting rolling engagement between the ceramic airfoil and the metallic support carrier

Methodology Applied

Scientific EffectRolling contact: Roller

Data Source

PatentUS11149567B2Ceramic matrix composite load transfer roller joint

Publication Date: 2021.10.19 ROLLS ROYCE CORP

AI summary

An airfoil assembly includes a roller joint formed between a ceramic airfoil portion and a carrier allowing sliding (rolling) radial movement therebetween to accommodate thermal growth disparity.