Printed Pattern Composite Fibers for Interlaminar Strength and Tack

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Solution Overview

Problem

Conventional composite laminates face issues such as separation at the resin-fiber interface, low interlaminar shear strength, low electrical conductivity, and susceptibility to corrosion, which affect their performance and manufacturing complexity.

Innovation Solution

A composite structure where a second material is systematically deposited onto reinforcing filaments in a printed pattern, altering properties like crack resistance, interlaminar shear strength, electrical conductivity, and tack, using techniques like inkjet printing or extrusion to control the length, width, and thickness of the deposited material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermoplastic material is randomly distributed in bulk throughout a composite layup, then mode II interlaminar strength is improved, but mode I interlaminar strength remains low and crack propagation is not prevented

Engineering Contradiction:
Improvemode II interlaminar strengthVSAvoidcrack propagation resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local quality by transitioning from random bulk distribution to targeted placement of thermoplastic material. The printed circuit board incorporates thermoplastic material at specific locations where crack-arresting features are needed, such as at the resin-fiber interface and within fiber tows. This localized approach improves mode I interlaminar strength and prevents crack propagation while maintaining mode II interlaminar strength enhancements.

Inventive Principle:
Principle #3Local quality

2Reliability

If metallic meshes or foils are added across the surface of composite plies to improve electrical conductivity, then electrical conductivity is enhanced, but cost, complexity, and production time increase

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the electrical conductivity function with the existing printed circuit board traces. Instead of adding separate metallic meshes or foils, the thermoplastic material is integrated into the same printing process that creates the circuit traces. This combination achieves enhanced electrical conductivity while eliminating the need for additional metallic layers, thereby reducing manufacturing complexity and production time.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If fiberglass layer is added at the interface between composite laminate and metallic part to prevent corrosion, then corrosion resistance is improved, but cost and manufacturing complexity increase

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by making the thermoplastic material perform multiple functions simultaneously. At the interface between composite laminate and metallic parts, the thermoplastic material provides both crack-arresting features and corrosion protection. This multi-functional approach eliminates the need for separate fiberglass barrier plies, thereby reducing manufacturing complexity while maintaining enhanced corrosion resistance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Strength

If epoxy binders or nylons are added to dry fiber composite plies to improve tack, then tack is enhanced, but the range of temperatures and pressures required for ply stacking is limited

Engineering Contradiction:
ImprovetackVSAvoidtemperature and pressure range
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by utilizing the inherent temperature-dependent properties of thermoplastic material. The thermoplastic material is applied in a solid state at room temperature to provide immediate tack for ply stacking. During subsequent curing at elevated temperatures, the thermoplastic material transitions to a molten state, maintaining tack and enabling ply consolidation across a broad range of temperatures and pressures, thus overcoming the limitations of epoxy binders or nylons.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method enhances crack resistance, interlaminar shear strength, electrical conductivity, and corrosion resistance while improving tack, thereby stabilizing the composite structure and reducing manufacturing complexity.

Implementation Method 1

using techniques like inkjet printing or extrusion to control the length, width, and thickness of the deposited material

Methodology Applied
Scientific EffectInkjet printing:

Implementation Method 2

using techniques like inkjet printing or extrusion to control the length, width, and thickness of the deposited material

Methodology Applied
Scientific EffectExtrusion: Extrusion

Data Source

PatentEP3000922B1Printing patterns onto composite laminates
Publication Date: 2019.01.30 THE BOEING CO
  • EP3000922B1 patent drawingFigure 1

AI summary

A composite fiber may include at least one reinforcing filament formed of a first material. A second material maybe systematically deposited in a printed onto the at least one reinforcing filament such that at least one of a length, a width, and a thickness of the second material varies across a surface of the at least one reinforcing filament. The printed pattern may alter one or more properties of a composite structure containing the composite fiber.