NESB Nondestructive Evaluaton Sciences Branch

Shape Sensing Sensor using Optical Fibers

The shape sensing sensor technology co-locates Fiber Bragg Grating (FBG) sensors in the 3-core optical fiber. The sensing fibers are bonded or embedded in the airframe. Each of the 3 cores in the fiber is strained differently according to the bend radius and the FBG sensor gives 3 different strain measurements.

The shape algorithms calculates the strain at every discrete element along the fiber length and recontructs the fiber in 3D space curves.

• Surface shape mesurements can provide feedback in morphing wing systems.
• Multi-core fiber is highly flexible, conforms to shapes, and can be secured to an airframe using ordinary methods.
• Airframe or wing deflections induce bending along the multi-core fiber. Even during multi-axis bending, the fiber conforms to the surface.
• Fiber bending is measured and converted to 3D space curves using shape algorithms.
• Deviations from baseline shapes can indicate airframe fatigue