FRP Contamination Detection via Thermal Desorption

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Solution Overview

Problem

The repair of structural components made of fiber-reinforced plastics (FRP) using adhesive bonds is challenging due to potential contamination, which can severely impair adhesive strength, leading to potential failure, especially when exposed to ambient conditions with liquids or gases, and existing detection methods are complex and inefficient.

Innovation Solution

A compact, mobile device with a surface heating unit for thermal desorption of contaminants and a sensor array for simultaneous detection, eliminating the need for transport gases and allowing precise contamination measurement, featuring a contact heating device or radiant heating with temperature monitoring to prevent component damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are used to detect different contaminants, then detection capability is improved, but device complexity increases significantly

Engineering Contradiction:
Improvecontaminant detection capabilityVSAvoidsensor array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a sensor array where multiple sensors simultaneously detect different contaminants (water, oil, alcohol, solvent residues) in the desorbed gas phase. This multi-functional approach allows a single device to identify various contaminant types without requiring separate detection systems for each substance, resolving the contradiction between comprehensive detection and device complexity.

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

2Measurement precision

If heating temperature is increased to improve contaminant desorption, then detection sensitivity is improved, but risk of component damage increases

Engineering Contradiction:
Improvecontaminant desorption efficiencyVSAvoidcomponent damage risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates temperature monitoring during the heating process to ensure that the heating remains within safe limits for the FRP component. This feedback mechanism allows sufficient thermal energy to be applied for effective contaminant desorption while preventing temperatures that would damage the composite material, thus resolving the contradiction between desorption efficiency and component safety.

Inventive Principle:
Principle #23Feedback

3Speed

If transport gas is used to carry desorbed contaminants to sensors, then contaminant transport is improved, but detection sensitivity decreases due to gas dilution

Engineering Contradiction:
Improvecontaminant transport speedVSAvoidcontaminant concentration detection
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent extracts and detects contaminants directly in the gas phase after thermal desorption, without introducing additional transport gas that would dilute the contaminant concentration. The sensor array analyzes the desorbed gases directly at the heating location, eliminating the need for carrier gas and maintaining high detection sensitivity while still achieving effective contaminant transport to the sensors.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If comprehensive contaminant detection is implemented, then adhesive bond reliability is improved, but inspection time increases

Engineering Contradiction:
Improveadhesive bond reliabilityVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs contaminant detection continuously during the heating process rather than requiring separate inspection steps. The sensor array operates simultaneously with the thermal desorption, detecting contaminants as they are released from the FRP component. This continuous detection approach ensures comprehensive contaminant identification while minimizing total inspection time, resolving the contradiction between reliability and time efficiency.

Inventive Principle:
Principle #20Continuity of useful action

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 efficient and accurate detection of multiple contaminants without damaging the FRP components, allowing for reliable adhesive repair of FRP components in aviation, improving sensitivity and reducing equipment complexity.

Implementation Method 1

the heating process of the component is temperature-monitored so that no impermissibly high temperatures occur that could damage the component

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

thermal desorption of contaminants by direct heating of a region of the surface to be treated either by means of thermal conduction or thermal radiation

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

solid or liquid phases are converted directly into the gas phase

Methodology Applied
Scientific EffectSublimation: Sublimation

Implementation Method 4

solid or liquid phases are converted directly into the gas phase

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

surface heating device for regional heating of a portion of the fiber composite component to be bonded for the purpose of desorption of contaminants

Methodology Applied
Scientific EffectThermal desorption: Desorption

Data Source

PatentEP2710358B1Device for inspecting a fibre-composite component for contaminations
Publication Date: 2020.07.01 AIRBUS DEFENCE & SPACE GMBH
  • EP2710358B1 patent drawingFigure 1~3
  • EP2710358B1 patent drawingFigure 4~6

AI summary

A device and method for testing a fiber-composite component, which is to be processed by means of bonding, for the presence of at least one substance out of a selection of possible contaminants. A surface heating device for regional heating of a part-zone of the fiber-composite component to be bonded is performed for desorption of contaminants. A sensor array with a plurality of sensors detects contaminants in the gas phase, and a control device ascertains and signals contaminations which are found. An extractor device can be employed to extract machining dust from the fiber-composite component to a desorption device.