NASA Fiber Optic Sensing Technologies Dramatically Improve Structural Health Monitoring and Tank Gauging

Revolutionary FOSS technology offers a wealth of flexible options for a wide variety of applications

NASA’s Armstrong Flight Research Center is offering companies that provide sensing solutions for monitoring of structures and asset management of storage tanks a unique opportunity to expand their product line to include unprecedented capabilities.

Known as FOSS (for fiber optic sensing system), NASA’s patented, award-winning technology portfolio combines advanced strain sensors and innovative algorithms into a robust package that accurately and cost-effectively monitors a host of critical parameters in real time.

These capabilities have significant potential for structural health management and tank gauging applications.

Structural Health Monitoring

• https://www.fuentek.com/featured-tech/Shape and Position: Two- and three-dimensional (2D and 3D) displacement, deformation, deflection, twist, tilt, and rotation
• Stiffness: Bending, torsion, and vibration
• Operational Loads: Bending moments, shear loads, and torques
• Strength, Stress, and Fatigue: Pressure, acceleration, and breakage/failure prediction
• Magnetic Fields: Cracks or other flaws in safety-critical metal structures

Tank Gauging

In addition to monitoring the structure of a tank, FOSS is capable of sensing the tank’s inventory:

• Amount: Liquid level and evaporation rate
• Temperature: From cryogenic up to 300 degrees Celsius
• Stratification: Oil vs. water, sediment vs. liquid, and thermal layers

Manufacturers and end-users of structural and tank sensing solutions can tap into the superior performance of NASA’s FOSS system by licensing either the entire portfolio or only the easy-to-integrate elements that complement their existing products. Many of the FOSS technologies can be applied to OFDR-based systems, WDM-based systems, or both. Detailed information is provided below.

OFDR: optical frequency domain reflectometry
WDM: wavelength division multiplexing

For Example…

As a single example of the value FOSS can provide, consider oil and gas drilling applications. The FOSS technology could be incorporated into specialized drill heads to sense drill direction as well as temperature and pressure.

• Because FOSS accurately determines the drill shape, users can position the drill head exactly as needed.
• Temperature and pressure indicate the health of the drill.

This type of strain and temperature monitoring could also be applied to sophisticated industrial bore scope usage in drilling and exploration.

NASA Armstrong’s FOSS technology revolutionizes fiber optic sensing by using its innovative algorithms to calculate a range of useful parameters—any and all of which can be monitored simultaneously and in real time.

FOSS also couples these cutting-edge algorithms with a high-speed, low-cost processing platform and interrogator to create a single, robust, stand-alone instrumentation system. The system distributes thousands of sensors in a vast network—much like the human body’s nervous system—that provides valuable information.

Licensees can select whichever FOSS algorithms and other technologies meet the needs of their customers. Or they can license the entire portfolio to offer a new line of FOSS-based products.

How it Works

• Fiber Bragg grating (FBG) sensors are embedded in an optical fiber at intervals as small as 0.25 inches, which is then attached to or integrated into the structure.
• An innovative, low-cost, temperature-tuned distributed feedback (DFB) laser with no moving parts interrogates the FBG sensors as they respond to changes in optical wavelength resulting from stress or pressure on the structure, sending the data to a processing system.
• Unique algorithms correlate optical response to displacement data, calculating the shape and movement of the optical fiber (and, by extension, the structure) in real time, without affecting the structure’s intrinsic properties.
• The system uses these data to calculate and display additional parameters.

Why It’s Better

• FOSS monitors a plethora of engineering measurements in real time with a single instrumentation system weighing less than 10 pounds.
• FOSS can discern between liquid and gas states in a tank or other container, providing accurate measurements at 0.25-inch intervals.
• Adaptive spatial resolution features enable faster signal processing and precision measurement only when and where it is needed, saving time and resources. As a result, FOSS lends itself well to long-term bandwidth-limited monitoring of structures that experience few variations but could be vulnerable as anomalies occur (e.g., a bridge stressed by strong wind gusts or an earthquake).