3D Woven Composite Preform for Window Frame Legs and Joggles

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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 to form upstanding legs and joggles without darts, allowing continuous fiber reinforcement and reduced weight through a differential take-up mechanism on a loom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If traditional composite window frames use labor-intensive darting to form upstanding legs and joggles, then complex shapes can be achieved, but strength is reduced and weight increases

Engineering Contradiction:

Improvecomplex shapeVSAvoidstrength

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The fabric is divided into multiple layers with different fiber orientations (0°, 90°, ±45° plies) that are woven separately and then bonded together. This segmentation allows each layer to provide specific structural functions while maintaining overall strength, eliminating the need for weak dart joints to form complex shapes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses multi-ply composite fabric structures where layers of carbon fiber reinforced polymer are bonded together with adhesive. This composite approach enables the formation of complex three-dimensional shapes with upstanding legs and joggles while maintaining high strength, replacing the weak dart joints of traditional single-layer construction

Inventive Principle:

Principle #40Composite materials

2Shape

If traditional composite window frames use labor-intensive darting processes, then complex shapes can be formed, but manufacturing complexity and time increase

Engineering Contradiction:

Improvecomplex shapeVSAvoidmanufacturing complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The fabric layers are pre-cut and pre-positioned in their final configuration before bonding. The multi-ply fabric structure is prepared in advance with all necessary cuts and shapes, then bonded in a single operation. This preliminary preparation eliminates the need for sequential darting operations during manufacturing, reducing both complexity and time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Multiple fabric layers are bonded together in a single manufacturing step to form the complete window frame structure. The bonding process combines shaping and structural assembly simultaneously, eliminating the need for separate darting and assembly operations. This merging of operations simplifies the manufacturing process while achieving complex shapes

Inventive Principle:

Principle #5Merging (Combining)

3Shape

If traditional composite window frames use darting to form upstanding legs, then three-dimensional features can be created, but continuous fiber reinforcement is lost

Engineering Contradiction:

Improvethree-dimensional featureVSAvoidcontinuous fiber reinforcement

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The multi-ply fabric structure uses continuous fiber reinforcement in each layer that is bonded to adjacent layers. The carbon fiber tows run continuously through the bonded plies, maintaining reinforcement integrity. This composite construction creates three-dimensional features like upstanding legs while preserving continuous fiber paths, eliminating the discontinuities created by dart joints

Inventive Principle:

Principle #40Composite materials

4Object-affected harmful factors

If traditional composite window frames use metallic frames with barrier plies, then corrosion protection can be achieved, but weight increases

Engineering Contradiction:

Improvecorrosion protectionVSAvoidweight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The invention changes the material parameter from metallic frame to all-composite construction. The window frame is made entirely of carbon fiber reinforced polymer, matching the fuselage material properties. This eliminates galvanic corrosion between dissimilar metals and composites, removing the need for barrier plies and reducing overall weight while maintaining corrosion protection

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8969223B2Woven preform, composite, and method of making thereof

Publication Date: 2015.03.03 ALBANY ENGINEERED COMPOSITES INC

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.