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Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †

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ABSTRACT

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.

No MeSH data available.


Shear stress distribution along the twisted rod/fiber.
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sensors-17-00443-f007: Shear stress distribution along the twisted rod/fiber.

Mentions: When a solid rod, for example an optical fiber, is exposed to torsional twist around its longitudinal axis, a twist induced share stress is generated with the twisted rod/fiber [30]. The share stress is zero at the center of the rod/fiber and increases linearly proportional towards the rod/fiber’s outer edge, where it reaches the maximum value (Figure 7). The share stress vector can be decomposed further into longitudinal and radial components (the first being parallel with the fiber’s axis and the second perpendicular to the fiber’s axis). Stressed regions of the fiber undergo refractive index changes, which are proportional to local stress and the material’s elasto-optics coefficients. This means that the stress induced refractive index change in a twisted optical fiber will be the highest at the outer edge of the fiber and zero in the center of the fiber.


Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †
Shear stress distribution along the twisted rod/fiber.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5375729&req=5

sensors-17-00443-f007: Shear stress distribution along the twisted rod/fiber.
Mentions: When a solid rod, for example an optical fiber, is exposed to torsional twist around its longitudinal axis, a twist induced share stress is generated with the twisted rod/fiber [30]. The share stress is zero at the center of the rod/fiber and increases linearly proportional towards the rod/fiber’s outer edge, where it reaches the maximum value (Figure 7). The share stress vector can be decomposed further into longitudinal and radial components (the first being parallel with the fiber’s axis and the second perpendicular to the fiber’s axis). Stressed regions of the fiber undergo refractive index changes, which are proportional to local stress and the material’s elasto-optics coefficients. This means that the stress induced refractive index change in a twisted optical fiber will be the highest at the outer edge of the fiber and zero in the center of the fiber.

View Article: PubMed Central - PubMed

ABSTRACT

Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.

No MeSH data available.