Steered Fabric Reinforcement for Darted Composite Preforms
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Solution Overview
Problem
Existing reinforced composite materials face challenges in creating strong joints for complex shapes, particularly curved surfaces, as darting the fibers to accommodate curvature breaks the continuity of the reinforcing material, degrading load-carrying capabilities.
Innovation Solution
A steered fabric reinforcement is woven to occupy the clevis between the legs of a 3D Pi preform, providing continuous fibers that match the curved pattern and affixed to the darted preform, restoring the load-carrying capability by creating a new path for stress transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the preform is darted to accommodate curved surfaces, then the preform can be shaped into complex curved forms, but the continuity of the reinforcing material is broken, degrading load-carrying capabilities
Solution Approach 1:
The reinforcement system is segmented into two distinct components: the darted preform that accommodates the curved surface geometry, and the separate steered fabric reinforcement that provides continuous load-carrying paths. This segmentation allows each component to optimize its function without compromise.
Solution Approach 2:
The steered fabric acts as an intermediary element between the darted preform and the external loads. It bridges the gaps created by darting, providing a continuous reinforcement path that transfers stresses around the curved regions without relying on the interrupted fibers of the darted preform.
2Ease of manufacture
If traditional reinforcement methods are used for darted preforms, then manufacturing is simpler, but stress transfer is inadequate and joints become weak links
Solution Approach 1:
The solution employs a composite reinforcement system combining two different fabric types with distinct functions: the darted preform provides geometric conformity to curved surfaces, while the steered fabric provides optimized load paths. This composite approach achieves both manufacturing feasibility and structural reliability.
Solution Approach 2:
The steered fabric is strategically placed in specific regions where stress concentration occurs due to darting, particularly in the clevis area between preform legs. This localized reinforcement provides enhanced stress transfer capability exactly where needed, without requiring complete redesign of the entire structure.
3Strength
If continuous fibers are maintained for load carrying, then strength is preserved, but the preform cannot be shaped into highly curved configurations
Solution Approach 1:
The reinforcement system is segmented into two distinct components: the darted preform that accommodates the curved surface geometry, and the separate steered fabric reinforcement that provides continuous load-carrying paths. This segmentation allows each component to optimize its function without compromise.
Solution Approach 2:
The solution adds a dimensional layer by placing the steered fabric as a separate reinforcement layer within the composite structure. This additional dimensional layer provides continuous load paths in three-dimensional space, bypassing the limitations of the two-dimensional darted preform geometry.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A reinforcement (201) for a darted three-dimensional Pi or T-shaped preform (101), a method of making thereof and a composite structure including the reinforcement is disclosed. The reinforcement is a steered fabric having a width, a length, a first face surface (212) and a second face (213) surface separated by a thickness (+). The first face surface of the steered fabric is affixed to a darted component of the preform.