Smart Multi-Layer Composites With Graphene Damage Detection

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Solution Overview

Problem

Multi-layer composites used in structural applications like cars and airplanes are vulnerable to internal damage from impulsive loads, making it difficult to detect and diagnose damage without external sensors, which complicates maintenance and safety.

Innovation Solution

Incorporating a graphene layer between the layers of the composite, which utilizes its piezo-resistive characteristics to detect changes in resistance and identify internal damage without the need for additional strain sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a composite structure is used to achieve lightweight and high strength, then mechanical performance is improved, but internal damage detection becomes difficult

Engineering Contradiction:
Improvemechanical strengthVSAvoidinternal damage detection
Core Design Contradiction:
StrengthVSDifficulty of detecting and measuring

Solution Approach 1:

A graphene layer is introduced as an intermediary between the composite layers. This graphene layer serves as a mediator that converts internal mechanical damage into detectable electrical resistance changes, enabling non-contact detection of damage without compromising the structural integrity or mechanical strength of the composite.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes resistance changes in the graphene layer as an indicator of internal damage. By monitoring electrical resistance (analogous to color changes in visual detection), the system can detect and locate damage within the composite structure without physical inspection, transforming an invisible damage state into a measurable signal.

Inventive Principle:
Principle #32Color changes

2Difficulty of detecting and measuring

If additional strain sensors are installed to detect internal damage, then detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvedamage detection capabilityVSAvoidsensor system complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The graphene layer performs multiple functions simultaneously: it acts as a structural component within the composite, provides electrical conductivity for resistance-based damage detection, and serves as a sensing element. This multi-functionality eliminates the need for separate strain sensors, reducing device complexity while maintaining detection capability.

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

Solution Approach 2:

The graphene layer is integrated directly into the composite structure, allowing it to self-monitor its own structural integrity through resistance changes. The damage detection function is embedded within the material itself rather than requiring external sensing systems, enabling the structure to detect its own damage states.

Inventive Principle:
Principle #25Self-service

3Reliability

If the composite structure is made more robust to withstand impulsive loads, then reliability is improved, but damage visibility from outside deteriorates

Engineering Contradiction:
Improveresistance to impulsive loadVSAvoiddamage visibility
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The graphene layer functions as an intermediary that bridges the gap between internal damage and external detection. It translates internal mechanical stress and damage into electrical resistance changes that can be measured from the outside, maintaining both the robustness of the composite structure and the visibility of its damage states.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables easy diagnosis of internal damage and rapid identification of damage location, improving safety by allowing for targeted repairs and reducing the need for replacing entire structures.

Implementation Method 1

it is possible to easily diagnose internal damage occurring during use by using a piezo-resistive characteristic of the graphene layer

Methodology Applied
Scientific EffectPiezo-resistive effect: Piezoresistive Effect

Data Source

PatentUS9358757B2Smart multi-layer composites
Publication Date: 2016.06.07 CHAI KYUNG NAM

AI summary

A smart multi-layer composite is disclosed. The smart multi-layer composite includes a plurality of layers stacked in sequence; and a graphene layer interposed between the plurality of layers.