Flexible CMC Seal Structure for Thermal Expansion Gaps
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Solution Overview
Problem
Conventional ceramic matrix composite (CMC) materials lack sufficient flexibility, making them unsuitable for high-temperature applications requiring thermal expansion and aerodynamic sealing in aerospace systems.
Innovation Solution
The method involves joining ceramic matrix composite lamina with reduced inter-laminar bonding regions, using a bond-inhibiting material between layers to create gaps and enhance flexibility, allowing for thermal expansion and improved sealing in high-temperature environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional CMC materials are used, then high-temperature stability and structural integrity are achieved, but flexibility and compliance are insufficient
Solution Approach 1:
The CMC structure is divided into multiple discrete lamina layers that can move independently relative to each other. This segmentation allows each layer to maintain structural integrity at high temperatures while collectively providing flexibility through inter-laminar movement, directly resolving the contradiction between temperature stability and flexibility.
Solution Approach 2:
The patent applies different bonding characteristics to different regions of the CMC structure. Some inter-laminar regions are fully bonded to maintain structural integrity, while other regions are left unbonded or partially bonded to provide flexibility. This local differentiation allows the structure to simultaneously achieve high-temperature stability in bonded regions and flexibility in unbonded regions.
2Object-affected harmful factors
If gap covers are added to cover thermal expansion spaces, then aerodynamic performance is improved, but flexibility and compliance are reduced
Solution Approach 1:
The patent replaces rigid gap cover structures with flexible CMC lamina assemblies that can deform and conform to thermal expansion movements. The thin-film nature of the lamina allows them to act as flexible seals that maintain aerodynamic continuity while accommodating compliance requirements, resolving the contradiction between drag reduction and flexibility.
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 approach results in CMC structures with increased flexibility, enabling them to withstand thermal expansion without damage and providing effective sealing in high-temperature applications, such as thermal protection systems.
Implementation Method 1
The methods include joining at least two lamina together so as to provide at least one bonded region and at least one region having at least reduced inter-laminar bonds to form a CMC structure. The lamina are joined by laying up lamina with a bond-inhibiting material or structure positions therebetween and sintering the lamina to form a CMC structure.
Data Source
Figure 1A~1B
Figure 1C~2
Figure 3A~3B
AI summary
Methods of forming ceramic matrix composite structures include joining at least two lamina together to form a flexible ceramic matrix composite structure. Ceramic matrix composite structures include at least one region of reduced inter-laminar bonding at a selected location between lamina thereof. Thermal protection systems include at least one seal comprising a ceramic matrix composite material and have at least one region of reduced inter-laminar bonding at a selected location between lamina used to form the seal. Methods of forming thermal protection systems include providing one or more such seals between adjacent panels of a thermal protection system.