Advanced Fiber Placement for Ceramic Matrix Composite Structures
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Solution Overview
Problem
Conventional methods for forming ceramic matrix composite (CMC) structures, such as resin transfer molding, chemical vapor infiltration, and hand placement, face limitations in scalability, uniformity, cost-effectiveness, and versatility, leading to challenges in achieving desired properties for industrial and military applications.
Innovation Solution
The method involves using an advanced fiber placement apparatus to place prepregged composite materials comprising ceramic fiber preforms infiltrated with a pre-ceramic matrix slurry over a tool, followed by curing and densification processes to form CMC structures, allowing for faster, more cost-effective, and versatile production of CMC structures of various shapes and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resin transfer molding (RTM) is used to form CMC structures, then the process can be automated and production speed improved, but the structures are limited to relatively small sizes and exhibit ceramic matrix uniformity issues due to gas bubbles
Solution Approach 1:
The patent extracts and removes gas bubbles from the ceramic matrix composite structure during the manufacturing process. The system includes a vacuum chamber that evacuates the mold cavity before and during resin infusion, and continues to evacuate during curing and pyrolysis, actively removing gas bubbles that would otherwise become trapped in the ceramic matrix and compromise uniformity.
Solution Approach 2:
The patent performs preliminary evacuation of the mold cavity before introducing the resin slurry. The vacuum chamber is evacuated to a predetermined vacuum level prior to resin infusion, and the mold remains under vacuum during subsequent curing and pyrolysis processes, preventing gas bubble formation and entrapment before they can affect matrix uniformity.
2Manufacturing precision
If chemical vapor infiltration (CVI) is used to form CMC structures, then uniform ceramic matrix can be achieved, but complex and costly tooling is required and tool reusability is limited
Solution Approach 1:
The patent employs a mold that serves multiple functions: it shapes the ceramic fiber preform, contains the resin slurry during infiltration, maintains vacuum conditions during curing, and facilitates pyrolysis. This multi-functional mold eliminates the need for separate, specialized tooling for each processing step, reducing overall tooling complexity and cost while maintaining matrix uniformity.
Solution Approach 2:
The patent changes the physical and chemical parameters of the resin slurry in situ within the mold during processing. The slurry transitions from a liquid state during infiltration to a cured state, and then undergoes pyrolysis to form the ceramic matrix. These parameter changes occur within the same mold structure, eliminating the need for multiple specialized tools.
3Adaptability or versatility
If hand placement of ceramic fiber preforms is used, then flexibility in shaping complex structures is achieved, but the process is time-consuming and labor-intensive
Solution Approach 1:
The patent replaces manual mechanical placement operations with automated resin slurry infiltration. The fiber preform is placed in the mold and then automatically infused with resin slurry under vacuum conditions, eliminating the need for manual manipulation and significantly reducing labor time while maintaining the ability to form complex structures.
Solution Approach 2:
The resin slurry automatically infiltrates the fiber preform through capillary action and vacuum pressure, eliminating the need for manual application. The system self-regulates the infiltration process, and the mold itself facilitates the curing and pyrolysis processes, reducing the need for continuous manual intervention.
4Productivity
If filament winding of ceramic fiber tows is used, then production speed can be increased, but the process is limited to substantially cylindrical shapes
Solution Approach 1:
The patent uses a mold with a movable or adjustable fiber placement system that can adapt to various mold geometries. The resin slurry infiltration process is dynamic, allowing the resin to flow and penetrate fibers in complex three-dimensional arrangements, enabling the formation of non-cylindrical and complex shapes while maintaining automated high-speed production.
Solution Approach 2:
The patent transitions from two-dimensional filament winding to three-dimensional resin slurry infiltration. The liquid resin can penetrate and bind fibers in complex three-dimensional configurations within the mold, enabling the formation of arbitrarily complex geometries rather than being constrained to cylindrical shapes.
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 rapid and cost-effective production of CMC structures with improved properties like high temperature stability, thermal resistance, and corrosion resistance, facilitating their use in complex industrial and military applications.
Implementation Method 1
a pre-ceramic matrix slurry is infiltrated into the ceramic fiber preform
Implementation Method 2
The uncured composite material structure is then cured
Implementation Method 3
The cured composite material structure is then pyrolyzed to form the CMC structure
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method of forming a ceramic matrix composite structure. The method comprises forming at least one prepregged composite material comprising a ceramic fiber preform and a pre-ceramic matrix slurry. The ceramic fiber preform may comprise a single tow of ceramic fibers, a tape of multiple tows or a woven fabric. The at least one prepregged composite material is placed over at least one surface of a tool using an advanced fiber placement apparatus to form an at least partially uncured composite material structure. The at least partially uncured composite material structure is exposed at least to elevated temperatures to convert the at least partially uncured composite material structure into a ceramic matrix composite structure. A system for forming a ceramic matrix composite structure, an advanced fiber placement apparatus, and a ceramic matrix composite structure are also described. The ceramic matrix can be both an oxide and non-oxide.