Ceramic Matrix Composite Repair Joining With Off-Plane Fiber Plies
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Solution Overview
Problem
CMC components in gas turbine engines are prone to damage and wear, leading to gaps and reduced structural integrity due to off-plane fiber directions in repair plies, which compromise laminar organization and infiltration efficiency.
Innovation Solution
The method involves placing joining plies with off-plane fiber directions relative to existing plies to improve laminar organization and infiltration, using a ply stack configuration that alternates fiber directions to enhance structural strength and retention mechanisms, followed by heating processes like melt infiltration or brazing to fuse the plies to the repair area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If joining plies with off-plane fiber directions are placed on the repair area, then delamination is reduced and mechanical strength is improved, but the laminar organization is compromised and infiltration efficiency is reduced
Solution Approach 1:
The patent applies different fiber orientation strategies to different regions of the repair area. Base plies are oriented parallel to the surface to maintain laminar organization and facilitate infiltration, while joining plies are oriented off-plane (45-90 degrees) to specific regions where delamination resistance is needed. This localized differentiation resolves the contradiction by providing each region with the specific fiber orientation it requires for optimal performance.
Solution Approach 2:
The patent creates a composite ply structure combining plies with different fiber orientations (parallel and off-plane) in a single repair assembly. This composite approach allows the repair structure to simultaneously achieve good laminar organization from parallel plies and enhanced delamination resistance from off-plane plies, resolving the technical contradiction through material composition rather than single-orientation uniformity.
2Strength
If joining plies with off-plane fiber directions are placed on the repair area, then mechanical strength is improved, but infiltration efficiency is reduced
Solution Approach 1:
The patent strategically positions off-plane joining plies only in specific regions where strength enhancement is most needed, while maintaining parallel-oriented plies in areas critical for infiltration access. This localized application ensures that infiltration pathways remain unobstructed in key regions while still achieving delamination resistance where structural demands are highest.
Solution Approach 2:
The patent uses a moderate number of off-plane joining plies rather than completely covering the repair area. This partial application provides sufficient delamination resistance and mechanical strength improvement without excessively compromising infiltration efficiency, achieving an optimal balance between the two competing requirements.
3Strength
If a ply stack configuration with alternating fiber directions is used, then structural strength and retention mechanisms are enhanced, but the complexity of the repair process increases
Solution Approach 1:
The patent segments the repair plies into distinct functional groups: base plies for laminar organization, joining plies for delamination resistance, and surface plies for final finishing. Each segment has a specific fiber orientation purpose, making the overall complex structure manageable through functional decomposition and systematic assembly procedures.
Solution Approach 2:
The patent prepares the ply stack configuration in advance with pre-determined fiber orientations and layer sequences. By pre-organizing the alternating fiber direction pattern before application to the repair area, the complexity of achieving proper structural strength is reduced during the actual repair process, as the orientation scheme is already established rather than requiring complex real-time adjustments.
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 enhances the mechanical strength and durability of repaired CMC components by reducing delamination and improving load transfer, while maintaining structural integrity and facilitating further repair operations.
Implementation Method 1
heating processes like melt infiltration or brazing to fuse the plies to the repair area
Implementation Method 2
heating processes like melt infiltration or brazing to fuse the plies to the repair area
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method (200) for repairing a ceramic matrix composite (CMC) component (60) includes laying joining plies (70) onto a repair area (68) of the CMC component (60) having a fiber direction (80) transverse to a fiber direction (80) of one or more composite plies (76) of the repair area (68) and heating the CMC component (60) to fuse the joining plies (70) to the repair area (68).