Laminate Interface Reinforcement with Nanoparticles

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Solution Overview

Problem

Laminate fiber-reinforced composites are weak at the interfaces between layers due to localized polymer-rich regions, which are points of weakness in interlaminar tension and shear, while being stronger in the plane of the fibers.

Innovation Solution

Incorporating secondary reinforcement nanoparticles, such as carbon nanotubes, concentrated at the interfaces between fiber layers to enhance the strength of these weak areas, while maintaining a lower concentration in the bulk matrix to avoid agglomeration and improve bonding with the polymer matrix.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If secondary reinforcement nanoparticles are added to strengthen interfaces, then interlaminar strength is improved, but nanoparticle agglomeration occurs in the bulk matrix

Engineering Contradiction:
Improveinterlaminar strengthVSAvoidnanoparticle distribution uniformity
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by concentrating secondary reinforcement nanoparticles specifically at the fiber layer interfaces rather than uniformly distributing them throughout the bulk matrix. This localized concentration strengthens the weak interface regions without causing agglomeration in the bulk, as the nanoparticles are confined to specific zones where they are most needed for improving interlaminar strength.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If polymer-rich regions are present at interfaces, then layer bonding is facilitated, but interlaminar tension and shear strength decrease

Engineering Contradiction:
Improvelayer bondingVSAvoidinterlaminar tension and shear strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent addresses this contradiction by locally modifying the interface region with concentrated secondary reinforcement nanoparticles. The polymer-rich regions remain for bonding purposes, but the added nanoparticles at the interface provide additional strength to counteract the weakness caused by polymer concentration, thereby maintaining ease of manufacture while improving interlaminar tension and shear strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure at the interface by combining the polymer matrix with concentrated secondary reinforcement nanoparticles. This composite interface region maintains the bonding capabilities of the polymer-rich zone while adding the strength properties of the nanoparticles, effectively resolving the contradiction between ease of manufacture and interlaminar strength.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2977198B2Secondary reinforcement at interface of laminate structure
Publication Date: 2023.08.09 RTX CORP
  • EP2977198B2 patent drawingFigure 1~2
  • EP2977198B2 patent drawingFigure 3

AI summary

A composite article includes a laminate structure of at least first and second fiber layers. Each of the layers includes a network of primary reinforcement fibers disposed in a matrix. The layers are bonded to each other along an interface of the matrices. The matrices include a concentration of secondary reinforcement particles locally at the interface to strengthen the interface.