3D Woven Preforms With Through-Thickness Tows for CMC Integrity
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Solution Overview
Problem
Manufacturing three-dimensional woven fiber structures, particularly π-shaped structures for CMC components like blade outer air seals (BOAS), is challenging due to voids or cavities in the noodle region, leading to susceptibility to cracking and delamination, which compromises the strength and integrity of the components.
Innovation Solution
A single three-dimensional woven fiber structure is created with connecting weft tow sections that pass through the thickness of the base section, forming π-shaped structures with angled leg sections, which are then densified to form ceramic matrix composites, enhancing strength and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If 2D woven structure is folded to create angled leg sections, then the structure can be formed, but voids or cavities are created in the noodle region leading to cracking and delamination
Solution Approach 1:
The patent transitions from folding 2D woven structures to creating true 3D woven structures where leg sections extend vertically from the base section. This dimensional change eliminates the noodle region voids by forming continuous fiber paths through the thickness, resulting in improved structural integrity and resistance to cracking and delamination while maintaining the required angled configuration.
2Shape
If complex three-dimensional woven structure is formed by folding flat woven structures, then the shape is achieved, but the structure becomes difficult to form and densify
Solution Approach 1:
The patent employs preliminary action by pre-forming the 3D woven structure with leg sections extending vertically from the base section before densification. This preliminary configuration of the fiber architecture ensures that the complex π-shaped structure is already in place and properly oriented, making the subsequent densification process straightforward and ensuring uniform density throughout the component without requiring complex forming operations.
3Quantity of substance
If noodle region is filled with particulate material or filler fiber, then the void is filled, but the region remains difficult to densify and lacks strength
Solution Approach 1:
The patent extracts and eliminates the problematic noodle region entirely by adopting a true 3D woven structure where leg sections extend vertically from the base section. This removes the need for filler materials and eliminates the densification difficulties associated with the noodle region, resulting in uniform fiber distribution and enhanced strength through the thickness of the structure.
Data Source
AI summary
Woven fiber preforms are disclosed which have a base section and one or more leg sections positioned the base section, The base section and the leg sections together are a made of a single three-dimensional woven fiber structure comprising warp and weft fiber tows. The woven structure includes connecting weft tow sections that connect the base section to each of the leg sections. The connecting weft tow sections include through-the-thickness tow regions that pass from a leg section through the thickness (height) of the base section.