3D Woven Preform for Continuous-Fiber Composite Window Frames
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Solution Overview
Problem
Traditional composite window frames for aircraft face challenges in incorporating features like upstanding legs and joggles due to their oval shape, requiring labor-intensive darting that reduces strength and increases weight, while existing solutions lack continuous fiber reinforcement across interfaces.
Innovation Solution
A three-dimensional woven preform using warp steered fabric with stretch broken carbon fibers and conventional carbon fibers, integrated through a differential take-up mechanism on a loom, allowing continuous fiber reinforcement across the preform, including upstanding legs and joggles, eliminating the need for darting and enabling reduced weight and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional composite window frames use darting to form complex shapes like upstanding legs and joggles, then the frames can achieve the required geometric features, but the labor intensity increases and strength decreases
Solution Approach 1:
The fabric is divided into multiple layers with different fiber orientations (warp and weft layers) that can be independently positioned and consolidated. This segmentation allows complex 3D shapes to be formed by stacking and bonding separate fabric layers rather than cutting and darting a single layer, thereby maintaining continuous fiber reinforcement and strength.
Solution Approach 2:
The invention transitions from 2D fabric cutting and darting to 3D woven preform construction. By building up multiple fabric layers in the thickness dimension and consolidating them through heat and pressure, the process creates complex 3D geometric features (upstanding legs, joggles) while maintaining continuous fiber paths, eliminating the need for strength-reducing darts.
2Shape
If traditional composite window frames use darting to form complex shapes, then the required geometric features are achieved, but weight increases
Solution Approach 1:
By segmenting the structure into multiple fabric layers that can be independently optimized, the design places material only where structurally necessary. This eliminates the need for excess material required by darting methods, reducing overall weight while achieving the same complex geometry.
Solution Approach 2:
The 3D woven construction allows material to be distributed efficiently through the thickness dimension, creating complex shapes with minimal material usage. The layered architecture enables geometric features to be formed by layer stacking rather than material removal or addition, optimizing weight.
3Shape
If traditional composite window frames use darting, then complex shapes can be formed, but continuous fiber reinforcement is interrupted creating weak joints
Solution Approach 1:
The fabric system is segmented into multiple layers that are bonded together, allowing each layer to maintain its own continuous fiber reinforcement. The bonding interfaces between layers are designed to preserve fiber continuity, eliminating the discontinuities created by darting while still enabling complex 3D shapes.
Solution Approach 2:
By moving to 3D woven construction with multiple layers, the invention maintains continuous fiber reinforcement in-plane within each layer while using the thickness dimension to create complex geometry. This eliminates the need for out-of-plane darts that interrupt fiber continuity, preserving structural reliability.
4Strength
If warp steered fabric with multiple layers is used, then continuous fiber reinforcement and reduced weight are achieved, but manufacturing complexity increases
Solution Approach 1:
The fabric layers are pre-cut and pre-positioned in their final configuration before consolidation. The warp steered fabric is woven in advance with the desired fiber orientation and layer stacking sequence, so that during consolidation no complex real-time adjustments are needed. This preliminary preparation simplifies the actual manufacturing process while maintaining design complexity for performance.
Solution Approach 2:
The consolidation process uses heat and pressure to automatically bond the pre-positioned layers together without requiring complex manual assembly or real-time control systems. The material itself facilitates the bonding process through thermoplastic or thermoset matrix materials that cure under heat and pressure, reducing the need for complex external bonding equipment.
Data Source
AI summary
A three dimensional woven preform, a fiber reinforced composite incorporating the preform, and methods of making thereof are disclosed. The woven preform includes one or more layers of a warp steered fabric. A portion of the warp steered fabric is compressed into a mold to form an upstanding leg. The preform includes the upstanding leg and a joggle in a body portion. The body portion and upstanding leg are integrally woven so there is continuous fiber across the preform. A portion of the warp steered fabric includes stretch broken carbon fibers in the warp direction, and another portion includes conventional carbon fibers. The warp steered fabric can be woven on a loom equipped with a differential take-up mechanism. The warp steered fabric can be a single or multilayer fabric. The preform or the composite can be a portion of an aircraft window frame.