Radially Extending Composite Structures Without Darting

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Solution Overview

Problem

In aerospace applications, forming radially extending composite structures with fiber-reinforced materials often results in wrinkles or requires darting, which weakens the parts or makes radial extension impossible.

Innovation Solution

The method involves laying up ply layers with specific fiber orientations, such as 17.5 to 27.5 degrees relative to the ply layer edge, without darting, using pre-preg or dry fiber materials like tapes, woven fabrics, and non-crimp fabrics, and splicing patterned cut flags to maintain structural integrity and prevent wrinkles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fiber-reinforced composite materials are used to create lightweight high-strength structures, then weight is reduced and strength is improved, but radial extension becomes impossible or results in wrinkles that weaken the parts

Engineering Contradiction:

Improvestructural strengthVSAvoidradial extension capability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent changes the fiber orientation parameter from conventional axial or circumferential layouts to specific radial angles (17.5-27.5 degrees relative to ply layer edge). This parameter change enables the composite structure to achieve both high strength and radial extension capability without wrinkles, resolving the contradiction between structural integrity and radial flexibility.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses fiber-reinforced composite materials with specifically oriented plies to create a multi-layered structure that combines the benefits of lightweight construction with radial extension capability. The composite material system allows simultaneous achievement of strength and adaptability through controlled fiber placement.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If darting is used to allow radial changes and reduce wrinkle formation, then radial extension capability is improved, but the part strength is weakened

Engineering Contradiction:

Improveradial extension capabilityVSAvoidpart strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent eliminates darting by changing the fiber orientation parameter to 17.5-27.5 degrees, which naturally accommodates radial extension without requiring cutouts or darts. This parameter change resolves the contradiction by enabling radial capability through fiber angle optimization rather than geometric modifications that compromise strength.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional fiber orientation is used in radially extending parts, then manufacturing is simplified, but wrinkles form that weaken the structure

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstructural strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent specifies precise fiber orientation parameters (17.5-27.5 degrees) that eliminate wrinkle formation during manufacturing. This parameter optimization ensures that the laying up process produces wrinkle-free structures with high strength, resolving the contradiction between manufacturing ease and structural integrity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10668672B2Radially extending composite structures

Publication Date: 2020.06.02 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A composite structure having at least one radially extending part is provided. The composite structure is formed with ply layers. At least one of the ply layers used to form the radially extending part has fibers oriented at an angle offset from an edge of the at least one ply layer.