Corner Fitting with Continuous Fiber Reinforcement
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Solution Overview
Problem
Existing methods for joining composite components to form complex structures often result in weak junctures, particularly at corners, due to inadequate reinforcement across all three planes, leading to potential failure under stress and distortion when folding two-dimensional woven preforms into three-dimensional shapes.
Innovation Solution
A fiber-reinforced corner fitting preform with continuous fibers connecting all sides is created using a flat woven fabric, where sacrificial fibers are transferred and trimmed to ensure continuous reinforcement in three directions, allowing for integration into larger structures without distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate components are joined at corners to form complex structures, then structural complexity and adaptability are improved, but junction strength and reliability deteriorate due to weak junctures
Solution Approach 1:
The patent merges multiple reinforcement layers and fiber orientations into a single integrated corner fitting preform. The preform combines 0-degree, 90-degree, and bias fibers in multiple layers that are stitched together, creating a unified structure that provides continuous reinforcement across all three planes at the corner junction, eliminating weak junctures while maintaining structural complexity
Solution Approach 2:
The corner fitting preform uses composite construction with multiple fiber types and orientations bonded together through stitching. The combination of different fiber layers (0-degree, 90-degree, bias) creates a multi-directional reinforcement system that simultaneously achieves high strength at junctions and adaptability for complex three-dimensional structures
2Shape
If two-dimensional woven preforms are folded into three-dimensional shapes, then complex component formation is improved, but distortion and fiber misalignment occur at corners
Solution Approach 1:
The patent performs preliminary folding of the flat woven preform before final assembly, creating pre-formed three-dimensional shapes with integrated corner fittings. The corner fittings are stitched into the preform layers in advance, ensuring proper fiber alignment and positioning before the final curing process, thereby preventing distortion during subsequent handling and assembly
Solution Approach 2:
The patent transitions from two-dimensional woven fabric to three-dimensional structured preforms by incorporating multiple layers stitched at various angles. The corner fittings add a third dimension of reinforcement with fibers oriented at 0, 90, and bias angles, enabling complex three-dimensional shapes while maintaining fiber alignment through the stitching architecture
3Strength
If continuous fiber reinforcement is implemented across all three planes at corners, then strength and reliability are improved, but manufacturing complexity and production difficulty increase
Solution Approach 1:
The patent segments the corner fitting reinforcement into distinct functional layers: 0-degree fibers for longitudinal strength, 90-degree fibers for transverse strength, and bias fibers for angular reinforcement. Each layer is separately woven and then stitched together in a systematic sequence, making the complex multi-directional reinforcement manufacturable through standardized sequential processes
Solution Approach 2:
The corner fitting applies localized reinforcement specifically at the corner junctions where multiple planes intersect. The stitching density and fiber orientation are concentrated at the corner regions where strength is most critical, while the rest of the preform uses standard weaving patterns, thereby achieving high corner strength without uniformly increasing manufacturing complexity throughout the entire structure
4Reliability
If multiple stitching operations are performed to join preform layers, then fiber integration and junction strength are improved, but production time and manufacturing cost increase
Solution Approach 1:
The patent uses periodic stitching patterns where stitches are placed at regular intervals along the layers rather than continuous stitching. This periodic action provides sufficient fiber integration and layer bonding while leaving gaps that reduce stitching time and material consumption, thereby maintaining reliability without excessive production time
Solution Approach 2:
The corner fitting design enables continuous fiber paths that run through multiple layers without interruption. The stitching creates continuous load transfer paths between layers, allowing stress to flow continuously across the corner junction. This continuous fiber integration reduces the need for additional corrective stitching operations, improving productivity while maintaining fiber integration quality
Data Source
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AI summary
A comer fitting (10) and a method of forming a corner fitting including steps of providing a flat woven fabric (20) including a first woven portion having first and second direction woven fibers, a second woven portion adjacent the first woven portion having first direction fibers (28) and sacrificial second direction fibers (26) and a third semi-woven portion having first direction fibers selectively engaged by the sacrificial second direction yarns. The method further comprising steps of folding the flat woven fabric in at least one direction, and removing the sacrificial second direction fibers, wherein during removal, the sacrificial second direction fibers are replaced in the second woven portion by the first direction fibers of the third semi-woven portion and form a corner fitting having continuous fibers connecting all sides.