Hybrid PMC-CMC Tile Composite for High-Temp Heat Shielding
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Solution Overview
Problem
High-temperature metal alloys used in aircraft and rocket components are heavy and difficult to heat shield effectively, as existing polymer matrix composites (PMCs) and oxide ceramic matrix composites (CMCs) face issues with thermal expansion mismatch, leading to delamination and limited size applicability for hybrid structures.
Innovation Solution
A hybrid composite structure comprising a polymer matrix composite (PMC) layer bonded with a tile layer of oxide ceramic matrix composite (Ox/Ox CMC) tiles, where some tiles are inverted and overlap joints cover at least 50% of the surface area, forming a smooth continuous surface and allowing for thermal expansion compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PMC and Ox/Ox CMC are combined in a hybrid structure for heat shielding, then heat shielding effectiveness is improved, but thermal expansion mismatch causes delamination
Solution Approach 1:
The hybrid composite is segmented into distinct PMC and CMC layers with defined interfaces, allowing each material to perform its specialized function while maintaining overall structural integrity through controlled layering and bonding
Solution Approach 2:
The patent modifies the bonding interface parameters by creating a transition zone with intermediate thermal expansion properties and optimized bonding strength, allowing the hybrid structure to accommodate thermal expansion differences without delamination
2Object-affected harmful factors
If small Ox/Ox CMC tiles are assembled in a tessellated pattern, then thermal protection is provided, but thermal expansion causes butt joints to separate
Solution Approach 1:
The CMC tiles are pre-assembled into a tessellated pattern with intentional overlap joints before bonding to the PMC substrate, creating a configuration that anticipates and accommodates thermal expansion during service
Solution Approach 2:
The patent transitions from point-contact butt joints to area-contact overlap joints, adding dimensional coverage at the interfaces to distribute thermal expansion stresses across larger surface areas
3Weight of moving object
If PMC is used as a lighter weight alternative for metal structures, then weight is reduced, but heat shielding capability above 650°F is lost
Solution Approach 1:
The patent creates a hybrid composite material system combining PMC and CMC layers, where the PMC provides lightweight structural support and the CMC provides high-temperature thermal protection, achieving both weight reduction and enhanced heat shielding
4Temperature
If Ox/Ox CMC is used for heat shielding up to 2000°F, then thermal resistance is improved, but compressive strength and bearing strength are reduced
Solution Approach 1:
The patent merges the structural PMC layer with the thermal protection CMC layer into an integrated hybrid composite, where the PMC contributes compressive strength and the CMC contributes thermal resistance, achieving both properties simultaneously
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 hybrid composite provides effective heat shielding up to 2000°F, enabling larger surface coverage without delamination, and can be applied to complex contours, reducing thermal strain and direct heat exposure to the PMC layer.
Implementation Method 1
Oxide ceramic composites (Ox/Ox CMC's), on the other hand, can be used to provide effective heat shielding in applications up to about 2000° F. Ox/Ox CMC's have high temperature resistance and very low thermal conductivity
Implementation Method 2
Because the thermal expansion rates of Ox/Ox CMC's and PMC's are markedly different, as the hybrid structure heats up, the mismatch in thermal expansion causes the Ox/Ox CMC to delaminate and disbond from the PMC
Data Source
AI summary
A combination of a component and a composite, the composite having a) a PMC layer, and b) a tile layer comprising a plurality of Ox/Ox CMC tiles, each tile having: i) a central portion, ii) an outer portion and iii) one or more overlap joints formed by the overlapping of the outer portions of adjoining tiles so that hot gases entering a smooth top surface of the tile layer between abutting outer and central periphery segments must travel laterally between the overlapping outer portions of adjoining tiles to reach a top surface of the PMC layer. A method of heat shielding a component with a heat shielding composite comprising a) providing the composite and b) applying the composite to a surface of the component.