Separate Tow Tensioning for Wrinkle-Free Composite Preforms
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Solution Overview
Problem
The formation of fabric preforms for composite components often results in distortions, wrinkles, and non-uniformity due to the difficulty in wrapping fabrics around forms without imperfections, leading to compromised structural integrity and mechanical properties in the final composite parts.
Innovation Solution
The method involves separately tensioning axial or hoop tows of the fabric during wrapping to reduce or eliminate imperfections, allowing for a more controlled and dense wrapping process, which can be achieved using tensioning mechanisms such as clutches or weights connected to the axial tows, enabling differential payout and slip, thereby improving the fiber architecture and mechanical properties of the composite material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wrapping techniques are used to apply fabric around a form, then the process is simple and quick, but the fabric preform develops wrinkles, waviness, and distortion that compromise structural integrity
Solution Approach 1:
The fabric is divided into separate axial tows that can be independently tensioned and controlled during wrapping. Each tow is paid out from its own dispenser, allowing individual adjustment of tension and payout rate to eliminate wrinkles and waviness while maintaining manufacturing feasibility
Solution Approach 2:
The tension applied to each axial tow is independently controlled and adjusted during the wrapping process. By varying the tension parameters for different tows, the system eliminates fabric defects while managing the complexity through programmable control
2Strength
If fabric is wrapped around a form without separate tensioning, then the equipment and process are simple, but the fiber architecture is poor and mechanical properties are reduced
Solution Approach 1:
Multiple independent tensioning mechanisms are provided, with each mechanism controlling the tension of a specific axial tow. This segmentation allows precise control of fiber architecture to maximize mechanical properties while keeping each individual tensioning mechanism relatively simple
Solution Approach 2:
Each tensioning mechanism serves multiple functions: it controls tow tension, regulates payout rate, and maintains proper fiber spacing. This multi-functionality reduces the need for additional separate systems, managing overall device complexity while improving mechanical properties
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 results in a higher fiber-to-resin ratio and improved mechanical properties of the composite components by reducing wrinkles and waviness, leading to a more consistent and stronger final product with enhanced structural integrity.
Implementation Method 1
friction between fibers or fiber bundles
Implementation Method 2
separately tensioning each of the axial or hoop tows in the fabric
Data Source
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AI summary
Disclosed are methods and devices for the formation of fabric preforms (20) that may be subsequently impregnated with a resin to form a composite component (18). One end of a fabric (44) is received on the form (54) such that the axial tows (46) of the fabric (44) extend in a direction generally perpendicular to a central axis (C-C) of the form (54). At least some of the plurality of axial tows (46) are separately tensioned on an end of the fabric (44) not attached to the form (54) and the fabric (44) is wrapped around the form (54) by rotating the fabric (44) and form (54) relative to one another about the central axis (C-C).