CMC Insert Architecture for Crack Steering in High-Stress Components
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic matrix composite (CMC) components in gas turbine engines are prone to cracks in high-stress regions, leading to premature failure and increased repair/replacement costs, as existing methods do not effectively control crack growth or prevent re-initiation of localized damage.
Innovation Solution
The use of directionally controllable CMC inserts with mechanical interlocks, which are designed to steer future cracks into low crack growth regions, incorporating a method of fabrication that involves depositing a boron-nitride based coating system on SiC fibers and infiltrating with a matrix precursor material, forming prepreg tapes, and pyrolyzing to create a dense composite with optimized fiber architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC components are used in high-temperature gas turbine applications, then temperature resistance and energy efficiency are improved, but crack formation and component reliability deteriorate due to high stress regions
Solution Approach 1:
The patent applies local quality by creating a transition zone with modified fiber architecture and material composition specifically in high-stress regions. This transition zone has different properties from the bulk material, with optimized fiber orientation and density to locally enhance crack resistance where stresses are highest, while maintaining the overall high-temperature performance of the CMC component.
Solution Approach 2:
The patent implements preliminary action by pre-placing the transition zone with optimized fiber architecture before cracks can form. This preventive measure is built into the component design to proactively manage stress distribution and crack initiation pathways, rather than attempting to repair cracks after they occur.
2Ease of manufacture
If conventional CMC fabrication methods are used, then manufacturing simplicity is maintained, but crack control and damage prevention capabilities are insufficient
Solution Approach 1:
The patent applies segmentation by dividing the CMC component into distinct zones: a bulk region with standard fiber architecture and a transition zone with optimized fiber architecture. This segmentation allows different regions to have tailored properties for their specific functional requirements, with the transition zone specifically designed to control crack propagation while the bulk maintains manufacturing simplicity.
Solution Approach 2:
The patent implements parameter changes by modifying fiber orientation, fiber density, and material composition parameters in the transition zone compared to the bulk material. These controlled parameter changes enable precise crack control in high-stress regions while maintaining overall manufacturing feasibility through established CMC fabrication processes.
3Power
If CMC components operate above proportional limit, then energy efficiency and power output are improved, but defect formation and premature failure increase
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a transition zone with optimized fiber architecture that acts as a buffer against crack propagation. This transition zone is designed to absorb and redistribute stresses before they can cause catastrophic failure, providing a cushioning effect that allows the component to operate safely above its proportional limit without immediate failure from defect formation.
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 approach simplifies repair/replacement costs by preventing crack propagation and re-initiation of localized damage, extending the lifespan of CMC components by steering cracks into low stress regions, thereby reducing costly downtime and material loss.
Implementation Method 1
depositing a boron-nitride based coating system on SiC fibers
Implementation Method 2
infiltrating with a matrix precursor material, forming prepreg tapes
Implementation Method 3
pyrolyzing to create a dense composite with optimized fiber architecture
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A ceramic matrix composite (CMC) component including a plurality of layers of a CMC and a directionally controllable CMC insert. The directionally controllable CMC insert is disposed in the plurality of layers of a ceramic matrix composite. The directionally controllable CMC insert includes an optimized architecture to strengthen a high stress region of the CMC component. The directionally controllable CMC insert is geometrically configured and disposed within the plurality of layers of the CMC to redirect a crack in the CMC component toward a region of low crack growth driving force. A turbomachine and method of forming a turbomachine member including a plurality of layers of a CMC and having the directionally controllable CMC insert disposed in a shaped void are additionally disclosed.