Fiber Optic Cable Embedded FBG Corrosion Detection
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Solution Overview
Problem
Conventional corrosion detection systems face challenges in detecting corrosion at the interface between layers in materials, particularly in laminates, due to surface-mounted sensors that may miss early corrosion, and are not suitable for large surface areas or environments with size, weight, and power constraints, and lack real-time monitoring capabilities.
Innovation Solution
Embedding fiber optic cables with Fiber Bragg Gratings (FBGs) at the interface between layers, which experience mechanical strain from corrosion, causing a wavelength shift detectable by a photodiode, allowing for real-time corrosion detection without affecting the material's cross-sectional profile and with minimal SWaP requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface-mounted sensors are used for corrosion detection, then the system structure is simple, but corrosion at the interface between layers cannot be detected early
Solution Approach 1:
The fiber optic cable with FBG sensors is embedded within the laminate structure itself, nesting the sensing element inside the material being monitored. This allows direct detection of corrosion at the interface between layers, overcoming the limitation of surface-mounted sensors that cannot detect subsurface corrosion until it progresses significantly.
Solution Approach 2:
The invention transitions from surface-level corrosion detection to subsurface detection by embedding sensors within the multi-layer structure. This dimensional change enables monitoring of corrosion at the interface between layers, providing early detection capability that surface sensors cannot achieve.
2Area of stationary object
If surface sensors are deployed for large surface area monitoring, then coverage area increases, but sensor density and detection effectiveness decrease
Solution Approach 1:
The fiber optic cable contains multiple FBG sensors spaced at predetermined intervals along its length. This segmentation allows a single embedded cable to provide multiple detection points across large surface areas, maintaining high detection sensitivity while covering extensive areas that would require numerous surface-mounted sensors.
3Reliability
If traditional sensors are used in shipboard or aircraft environments, then corrosion detection is possible, but size, weight and power requirements are unacceptable
Solution Approach 1:
The invention replaces traditional electrical sensors and wiring systems with fiber optic technology that uses light transmission instead of electrical signals. This substitution eliminates heavy electrical components, reducing the SWaP footprint while maintaining reliable corrosion detection capability in demanding environments like shipboard and aircraft applications.
Solution Approach 2:
The fiber optic sensors operate using optical parameters (light wavelength) rather than electrical parameters, fundamentally changing the detection mechanism. This parameter change enables corrosion detection with minimal SWaP, as fiber optic cables are lightweight, have no power requirements along their length, and are immune to electromagnetic interference.
4Productivity
If conventional corrosion inspection methods are used, then cost and time are reduced for simple cases, but real-time monitoring capability is lost
Solution Approach 1:
The embedded FBG sensors provide continuous real-time monitoring of corrosion conditions, eliminating the need for periodic manual inspections. The sensors continuously measure strain changes caused by corrosion progression, enabling ongoing assessment of material health and allowing transition from preventive maintenance to condition-based maintenance paradigms.
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 early detection of corrosion at the interface, reducing maintenance costs and extending the service life of materials like coated steel, facilitating a condition-based maintenance paradigm and providing immunity to electromagnetic interference.
Implementation Method 1
Each fiber optic cable can have a plurality of Fiber Bragg Gratings (FBG's) formed therein... Each FBG can have a preselected geometry that can only allow a predetermined light wavelength to pass therethrough... As corrosion occurs near an FBG, it experiences mechanical strain, which can further cause a slightly different wavelength to pass through the fiber optic cable. The change in in wavelength can be detected by the photodiode
Data Source
AI summary
Corrosion detection systems and methods can include at least one fiber optic cable embedded in a material having at least two layers. Two of the layers can define an interface, and the fiber optic cable can be embedded at the interface. Each fiber optic cable can have a plurality of Fiber Bragg Gratings (FBG's) formed therein at predetermined intervals. Each FBG can have a preselected geometry that can only allow a predetermined light wavelength to pass therethrough. A light source for inputting light and a photodetector can be connected to opposite exposed ends of the fiber optic cable. As corrosion occurs near an FBG, it experiences mechanical strain, which can further cause a slightly different wavelength to pass through the fiber optic cable. The change in in wavelength can be detected by the photodiode as being indicate of corrosion occurring at the site near the FBG.