Heat Shield Tile Mechanical Coupling for Thermal Stress

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Coupling heat shields to underlying structures in high-temperature environments is challenging due to material differences, which complicates traditional joining methods like welding or brazing, especially when using advanced materials with different thermal expansion coefficients.

Innovation Solution

A heat shield assembly featuring a metallic carrier with a heat-shield tile of different material, using mechanical attachment features such as dovetail shapes, hangers, and sintered components to securely couple the tile to the carrier, minimizing thermal stress and allowing for varying expansion rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional joining methods like welding or brazing are used to couple heat shields to underlying structures, then strong mechanical bonding is achieved, but thermal stress and material compatibility issues arise due to different thermal expansion coefficients

Engineering Contradiction:

Improvebonding strengthVSAvoidthermal stress resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The coupling system is divided into separate functional components: a mounting structure with mounting features that provides mechanical attachment, and a heat shield with a recess that receives the mounting structure. This segmentation allows each component to be optimized for its specific function while accommodating material differences through the mechanical interface design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mounting structure acts as an intermediary element between the heat shield and the underlying structure. It provides a transition zone that accommodates different materials and thermal expansion characteristics, eliminating the need for direct welding or brazing between dissimilar materials while maintaining strong mechanical coupling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If advanced materials with different thermal expansion coefficients are used to reduce cooling requirements and increase operating temperature, then thermal efficiency is improved, but coupling difficulty increases due to material incompatibility

Engineering Contradiction:

Improveoperating temperatureVSAvoidcoupling difficulty

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The system separates the heat shield material selection from the coupling mechanism. The mounting structure and heat shield are designed as distinct components with standardized mechanical interfaces, allowing advanced materials to be used in the heat shield without complicating the attachment process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mounting features are designed with geometric parameters (such as tapered surfaces and interference fits) that create secure mechanical coupling independent of material thermal properties. This allows different materials with varying thermal expansion coefficients to be coupled using the same standardized interface.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If mechanical attachment features are used to couple heat shields to carriers, then thermal stress is minimized and material compatibility is improved, but assembly complexity increases

Engineering Contradiction:

Improvethermal stress resistanceVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mounting features are designed as universal mechanical interfaces that can accommodate various heat shield materials and configurations. The standardized coupling mechanism serves multiple functions: mechanical attachment, thermal expansion accommodation, and alignment, simplifying the overall assembly process despite the sophisticated underlying mechanism.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 mechanical coupling ensures effective protection of the carrier from high-temperature exposure while accommodating different thermal expansion rates, facilitating the integration of advanced materials like ceramic matrix composites and nickel superalloys, and providing a robust and stress-minimized assembly.

Implementation Method 1

The inner mating surface and the outer mating surface may be ramped to cause the mount post to urge the heat-shield tile inwardly toward the base

Methodology Applied

Scientific EffectRamped surface mechanical conversion: Wedge

Implementation Method 2

The heat-shield tile includes material different than the carrier and is arranged to cover the carrier to protect the carrier from high-temperature air surrounding the heat shield assembly

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11873762B2High temperature heat shield assemblies

Publication Date: 2024.01.16 ROLLS ROYCE CORP

AI summary

A heat shield assembly adapted for use with gas turbine engines, airframes, and aircraft includes a carrier and a heat-shield tile. The carrier is adapted to couple to the gas turbine engine, airframe, or aircraft. The heat-shield tile includes material different than the carrier and is arranged to cover the carrier to protect the carrier from high-temperature gases surrounding the heat shield assembly.