Interdigitated Ceramic-Matrix-Composite Skin Assembly for Thermal Stress

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Solution Overview

Problem

Hypersonic vehicles experience high thermal stress due to their extreme operating conditions, leading to potential buckling of ceramic-matrix-composite skin panels, which are commonly used for their durability but have a higher coefficient of thermal expansion, posing challenges for maintaining an aerodynamic surface.

Innovation Solution

The implementation of a skin assembly with interdigitated ceramic-matrix-composite skin panels featuring staggered expansion gaps to accommodate thermal expansion, mitigating stress and buckling, and optionally incorporating an environmental barrier coating and a material that changes phase to hermetically seal the gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ceramic-matrix-composite skin panels are used for their durability, then reliability is improved, but thermal stress and buckling increase due to higher coefficient of thermal expansion

Engineering Contradiction:

ImprovedurabilityVSAvoidthermal stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The skin panel is segmented into multiple laminae with staggered lengths, creating expansion gaps between adjacent panels. This segmentation allows each panel to expand independently, reducing thermal stress while maintaining the durability of ceramic-matrix-composite material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the skin assembly have different properties: the ceramic-matrix-composite panels provide durability, while the expansion gaps provide thermal accommodation. This local differentiation allows each component to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

2Stress or pressure

If expansion gaps are introduced to accommodate thermal expansion, then thermal stress is reduced, but the aerodynamic surface continuity is compromised

Engineering Contradiction:

Improvethermal stressVSAvoidaerodynamic surface continuity

Core Design Contradiction:

Stress or pressureVSShape

Solution Approach 1:

The expansion gaps are positioned in the longitudinal direction (one dimension) while maintaining surface continuity in the lateral direction (another dimension). This dimensional separation allows thermal accommodation without compromising the aerodynamic surface appearance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The staggered laminae create asymmetric expansion gap patterns where gaps are offset between adjacent panels. This asymmetric arrangement allows thermal expansion while minimizing visual disruption to the aerodynamic surface continuity.

Inventive Principle:

Principle #4Asymmetry

3Stability of the object's composition

If staggered expansion gaps are created to mitigate buckling, then structural stability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvestructural stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The skin panel is manufactured as segmented laminae with predetermined staggered lengths, allowing expansion gaps to be created during assembly rather than requiring complex in-situ adjustments. This reduces manufacturing complexity while maintaining structural stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The laminae are pre-formed with specific staggered lengths before assembly, so that expansion gaps are automatically positioned correctly during panel joining. This preliminary preparation simplifies the overall manufacturing process while ensuring proper thermal accommodation.

Inventive Principle:

Principle #10Preliminary action

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 solution effectively mitigates thermal stress and buckling while maintaining an aerodynamic surface, adjusting gap distances for anticipated thermal conditions, and providing a hermetic seal to prevent oxidation.

Implementation Method 1

a material that changes phase to hermetically seal the gaps

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

the plurality of staggered expansion gaps are configured to accommodate thermal expansion of at least a portion of the skin assembly

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12404002B2Skin assembly and method for manufacturing the same

Publication Date: 2025.09.02 GENERAL ELECTRIC CO

AI summary

A skin assembly that includes a first ceramic-matrix-composite skin panel including one or more first fingers extending along a first direction. The skin assembly further includes a second ceramic-matrix-composite skin panel including one or more second fingers extending along the first direction. The one or more second fingers interdigitated with the one or more first fingers to define a plurality of staggered expansion gaps between the first ceramic-matrix-composite skin panel and the second ceramic-matrix-composite skin panel wherein the plurality of staggered expansion gaps are configured to accommodate thermal expansion of at least a portion of the skin assembly.