COPC Sensor for Aircraft Floor Beam Corrosion Detection

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Solution Overview

Problem

Current monitoring systems for detecting corrosive liquids in aircraft floor beam areas are inadequate due to limited space, difficulty in accessing hidden structures, and inability to distinguish between normal humidity variations and liquid ingress, leading to delayed detection of corrosion, which results in costly repairs and safety risks.

Innovation Solution

A sensor system utilizing a composite material with conductive particles dispersed in a hydrophilic matrix, tailored to remain conductive under normal conditions but transition to a non-conductive state upon liquid ingress, leveraging the collapse of percolation conductivity (COPC) to detect aqueous liquids, thereby providing an early warning for corrosion prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional monitoring systems are used to detect corrosive liquids in floor beam areas, then the system can provide continuous monitoring capability, but the system cannot distinguish between normal humidity variations and liquid ingress, leading to false alarms or missed detections

Engineering Contradiction:
Improvedetection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor utilizes the collapse of percolation conductivity (COPC) phenomenon, where the electrical conductivity of the composite material changes dramatically when liquid water is absorbed by the hydrophilic matrix. This parameter change from conductive to non-conductive state provides a clear binary signal that distinguishes liquid ingress from normal humidity variations, achieving high detection accuracy without complex signal processing systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sensor employs a composite material consisting of conductive particles dispersed in a hydrophilic matrix. This composite structure enables the material to absorb liquid water preferentially while maintaining electrical conductivity in the dry state. The unique combination of hydrophilic properties and electrical conductivity creates a material that responds specifically to liquid water ingress, providing precise detection capability

Inventive Principle:
Principle #40Composite materials

2Reliability

If sensors are installed in hidden floor beam areas to enable early detection, then corrosion prevention can start at an early stage, but the limited space and difficult accessibility make sensor installation and maintenance challenging

Engineering Contradiction:
Improvecorrosion prevention effectivenessVSAvoidsensor installation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sensor is designed as a thin, flexible composite material that can be conformally applied to the interior surfaces of floor beams. This thin-film configuration allows the sensor to adapt to the confined geometry of floor beam cavities, enabling installation in hard-to-reach areas while maintaining continuous monitoring coverage. The flexible nature of the thin film facilitates integration into existing structures with minimal disruption

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sensor system provides autonomous detection capability, automatically transitioning from a conductive to non-conductive state when liquid water is present. This self-service characteristic eliminates the need for complex power supplies, signal processing electronics, or manual calibration, simplifying both installation and maintenance operations in confined spaces

Inventive Principle:
Principle #25Self-service

3Reliability

If a sensor system is implemented to provide continuous monitoring of floor beam areas, then huge cost savings can be achieved through early detection, but the price of instrumentation and certification requirements increase initial costs

Engineering Contradiction:
Improvecorrosion detection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sensor utilizes inexpensive conductive particles and hydrophilic matrix materials that can be obtained from common commercial sources. The composite material formulation employs readily available components, significantly reducing material costs compared to specialized sensing materials. This cost-effective approach makes the sensor suitable for widespread deployment in aircraft structures

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The sensor replaces complex optical inspection systems (such as boroscopes) and manual inspection procedures with a simple electrical conductivity measurement system. By substituting mechanical/optical methods with electrical measurement, the system reduces instrumentation complexity and certification requirements, lowering overall system cost while maintaining reliable detection capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system effectively detects corrosive liquids with high sensitivity and specificity, reducing repair costs and enhancing safety by enabling early intervention against corrosion, even in confined and hard-to-reach areas, and can be implemented with reduced certification efforts.

Implementation Method 1

a lyophilic matrix for embedding the dispersed electrically-conductive material

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the concentration, dispersion and/or orientation of the electrically-conductive particles are tailored... in a way that the percolation conductivity is essentially interrupted if a relevant amount of solvent has entered the lyophilic composite

Methodology Applied
Scientific EffectPercolation conductivity collapse:

Data Source

PatentEP2593778B1Use of a sensor for detecting liquid spilling
Publication Date: 2018.04.11 KATHOLIEKE UNIV LEUVEN
  • EP2593778B1 patent drawingFigure 1
  • EP2593778B1 patent drawingFigure 2~3
  • EP2593778B1 patent drawingFigure 4

AI summary

Present invention concerns generally to a sensor or a sensor system for detecting spilling of aqueous liquids, for instance in confined spaces were such is critical such in an airplane. The system of present invention is an early warning system or sentinel for the prevention of corrosion by corrosive liquids. Corrosion caused by corrosive liquids can rapidly change the surface properties of components in engineering structures, and that will finally endanger the functionality of structural parts. However, if monitoring technologies are in place providing continuous information on the presence of corrosive liquids, corrosion treatment and even corrosion prevention can start at a very early stage. Present invention provides such by early detection of corrosive liquids by extended sensors based on the collapse of percolation conductivity (COPC). The term collapse refers to the fact that the transition into the non-conducting state must not necessarily have the properties of a thermodynamically well-defined transition.