Tackified Prepreg for CMC Fiber Alignment
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Solution Overview
Problem
Current methods for manufacturing gas turbine engine airfoils from ceramic matrix composites (CMCs) face challenges in maintaining fiber alignment and integrity during processing, which affects the durability and lightweight properties required for high-temperature applications.
Innovation Solution
A method involving a tackified prepreg process where unidirectional fibers are aligned with woven sections, treated with a pre-ceramic polymer tackifier, and stacked to form layers that are then wrapped around a mandrel, followed by resin injection, curing, machining, and pyrolysis to create a crystalline ceramic matrix composite with improved handling and alignment characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fiber weave is used to maintain fiber alignment, then fiber integrity is improved, but fiber alignment precision deteriorates due to woven sections interfering with unidirectional alignment
Solution Approach 1:
The fiber weave is segmented into unidirectional fiber sections by cutting through the woven sections, separating the continuous unidirectional fibers from the cross-fiber woven areas. This segmentation allows the unidirectional sections to be handled and stacked independently, maintaining fiber alignment precision while preserving the integrity provided by the original weave structure.
Solution Approach 2:
The unidirectional fiber sections are extracted from the woven fabric structure by cutting through the woven sections. This extraction removes the interfering cross-fiber woven sections while retaining the beneficial unidirectional fiber sections, enabling precise fiber alignment in the final stacked configuration without the destabilizing effect of the woven pattern.
2Manufacturing precision
If unidirectional fiber sections are separated from woven sections, then fiber alignment is improved, but handling difficulty increases due to lack of structural stability
Solution Approach 1:
A tackifier is applied to the unidirectional fiber sections before stacking to provide temporary adhesion. This preliminary action enables the separated unidirectional sections to be handled and stacked easily by allowing them to stick to one another during the stacking process, overcoming the handling difficulty that would otherwise result from separating them from the woven sections.
3Stability of the object's composition
If fiber weave structure is maintained, then structural stability is improved, but processing complexity increases for achieving desired article shapes
Solution Approach 1:
The fiber weave is segmented into unidirectional fiber sections by cutting through the woven sections. This segmentation simplifies processing by creating discrete sections that can be easily stacked and formed into complex article shapes, while the original weave structure is preserved within each section to maintain structural stability.
Solution Approach 2:
The processing approach transitions from working with continuous woven fabric in two dimensions to stacking separated unidirectional fiber sections in three dimensions. This dimensional change allows for more flexible formation of complex article shapes by stacking pre-cut sections, reducing processing complexity while maintaining the structural benefits of the original weave.
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 enables the production of CMC articles with enhanced fiber alignment and integrity, suitable for complex shapes and high-temperature applications, maintaining lightweight and durable properties while ensuring proper handling and processing characteristics.
Implementation Method 1
applying a tackifier to the fiber weave... The tackifier is a pre-ceramic polymer... arranging layers of the unidirectional fiber sections onto one another to provide a stack
Implementation Method 2
The article and resin are heated to high temperatures to pyrolyze the structure and form a crystalline ceramic metal matrix
Data Source
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AI summary
A method of creating a tackified prepreg includes steps of providing a fiber weave that have unidirectional fibers and woven sections spaced apart from one another to provide unidirectional fiber sections, applying a tackifier to the fiber weave, and separating the unidirectional fiber section from the woven sections.