Radius Fillers for Composite Structures with Oriented Tape Layers

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Solution Overview

Problem

Traditional radius fillers for composite structures lack tight control over shape and material properties, leading to distortion and mismatch with the surrounding composite material during formation and curing, necessitating improved methods for matching the shape and material properties of fillers to the void spaces in composite structures.

Innovation Solution

The method involves determining the transverse cross-sectional shape and material property field of the void space within the composite structure and forming radius fillers by combining lengths of composite tape with oriented reinforcing fibers to match the material properties of the transition region, ensuring a precise fit and minimizing distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional radius fillers are formed using single length of composite material creased to form accordion shape or stacked parallel planes, then the manufacturing process is simple, but the shape control and material property matching are poor

Engineering Contradiction:

Improveshape control precisionVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The radius filler is divided into multiple discrete composite tape layers, each contributing to the overall cross-sectional shape. This segmentation allows independent control of each layer's orientation and material properties, enabling precise matching to the void space geometry while maintaining manufacturability through standardized tape materials.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The composite tape layers are oriented at different angles relative to the longitudinal axis, creating local variations in material properties throughout the radius filler structure. This local quality variation allows the filler to match the anisotropic material properties of the surrounding composite structure at different locations, improving overall integration.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If radius filler material properties differ from surrounding composite material, then the filler can be manufactured independently, but distortion occurs during formation and curing

Engineering Contradiction:

Improvedimensional stability during curingVSAvoidindependent filler manufacturing

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The material properties of the radius filler are adjusted by changing the orientation angles of composite tape layers relative to the longitudinal axis. By varying these geometric parameters, the filler's material properties can be tuned to match the surrounding composite structure, ensuring dimensional stability during curing while maintaining independent manufacturability through standardized tape materials.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The radius filler is constructed as a composite structure itself, using multiple layers of composite tape with different fiber orientations. This composite construction allows the filler to achieve material properties that match the anisotropic characteristics of the surrounding composite structure, reducing distortion during formation and curing.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If the cross-sectional shape of radius filler does not match the void space shape, then manufacturing is easier, but distortion of composite structure occurs

Engineering Contradiction:

Improveshape matching precisionVSAvoidfabrication efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution moves from controlling only the cross-sectional shape to also controlling the fiber orientation dimension. By orienting composite tape layers at different angles relative to the longitudinal axis, the invention creates a three-dimensional material property distribution that matches both the geometry and material characteristics of the void space, achieving superior integration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10864687B2Radius fillers for composite structures, composite structures that include radius fillers, and systems and methods of forming the same

Publication Date: 2020.12.15 THE BOEING CO

AI summary

Radius fillers for composite structures and composite structures that include radius fillers are disclosed herein. The radius fillers include a plurality of lengths of composite tape. Each of the plurality of lengths of composite tape includes a respective plurality of lengths of reinforcing fibers and a resin material. The plurality of lengths of reinforcing fibers in each of the plurality of lengths of composite tape defines a fiber axis direction. Each of the plurality of lengths of composite tape defines a respective fiber axis direction that is based, at least in part, on material properties of a transition region defined by a plurality of plies of composite material that defines an elongate void space within which the radius filler is configured to extend. The composite structures include the radius fillers.