Variable Width Clevis 3D Preform for Distortion-Free Folding
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Solution Overview
Problem
Existing reinforced composite materials face challenges in creating strong structural joints without using adhesives or mechanical coupling, which can lead to weak links and distortion when folded into complex shapes, limiting their ability to withstand high out-of-plane loads and varying thickness requirements.
Innovation Solution
A method of weaving fiber preforms with variable width clevis and adjustable fiber lengths to minimize distortion and enhance structural integrity, allowing for the creation of 3D preforms that can be folded into shape without loops or ripples, using a sequence of warp fibers that adjust along the length to maintain fiber equality and interlock layers for improved load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If reinforcement preforms are joined at angles to create complex shapes, then the desired shape and structural strength are achieved, but the juncture becomes a weak link that can separate under tension due to peel forces
Solution Approach 1:
The preform is divided into multiple layers with warp fibers oriented in different directions. Each layer is segmented to create specific fiber pathways that continue through the joint, distributing loads across multiple fiber segments rather than relying on a single continuous joint strength.
Solution Approach 2:
The invention uses composite construction combining warp fibers and fill fibers in a woven structure. The fill fibers are specifically oriented to bridge the gap between angled preform sections, creating a composite joint structure that resists peel forces through the combined strength of both fiber types.
2Ease of manufacture
If uniform width clevis is used in Pi preform, then manufacturing is simplified, but weight efficiency is reduced due to inability to optimize thickness in different loaded areas
Solution Approach 1:
The clevis width is varied along the length of the preform to match the local structural requirements. The width is greater in areas requiring higher strength and smaller in areas with lower load requirements, optimizing the weight-to-strength ratio for each specific location in the joint.
3Shape
If preform is folded into complex shapes, then 3D configuration is achieved, but loops and ripples are produced causing distortion
Solution Approach 1:
The preform is pre-shaped and pre-stabilized during the weaving process before final assembly. The fiber pathways are established in advance to accommodate the final 3D configuration, so that when the preform is folded into its operational shape, the fibers are already positioned to minimize distortion and loop formation.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A woven preform (200) for a reinforced composite material, which may be woven flat and folded into shape. The preform (200) has a three-dimensional weave architecture with fill fibers woven to provide layer-to-layer interlocking of layers of warp fiber (216) as well as interlocking of fibers within each layer. At least two legs (225, 235) extend from a base (220), the base and legs each having at least two layers of warp fibers. The legs may be parallel or angled to each other, or may have a variable width clevis (250) in between. The outer ends of the base and/or the legs preferably have tapers formed from terminating layers of warp fibers in a stepped pattern.