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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.


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(a) Helical twist/rotation sensor setup; and (b) Multicore twist/rotation sensor setup.
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sensors-17-00443-f014: (a) Helical twist/rotation sensor setup; and (b) Multicore twist/rotation sensor setup.

Mentions: A relatively straightforward way to detect variations in the share stress distribution caused by twist/torsion in the transversal plane of the fiber is to use multicore fibers. When two (or multiple) cores are present at different radial positions within the fiber cross-section, shear stress will modify their indexes differently. The most straightforward way in the design of multicore twist/rotation sensors is to implement one core in the center of the fiber and one core at the fiber’s periphery. The sensitivity of such a sensor may be increased further by spinning the fiber during drawing, which creates a helical multicore fiber. Inscriptions of FBGs into central and peripherally positioned helical cores, while subtracting their characteristics’ wavelengths, allow for unambiguous (temperature and strain compensated) read-out of the fiber’s twist/torsion [79,80] (Figure 14a).


Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †
(a) Helical twist/rotation sensor setup; and (b) Multicore twist/rotation sensor setup.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

sensors-17-00443-f014: (a) Helical twist/rotation sensor setup; and (b) Multicore twist/rotation sensor setup.
Mentions: A relatively straightforward way to detect variations in the share stress distribution caused by twist/torsion in the transversal plane of the fiber is to use multicore fibers. When two (or multiple) cores are present at different radial positions within the fiber cross-section, shear stress will modify their indexes differently. The most straightforward way in the design of multicore twist/rotation sensors is to implement one core in the center of the fiber and one core at the fiber’s periphery. The sensitivity of such a sensor may be increased further by spinning the fiber during drawing, which creates a helical multicore fiber. Inscriptions of FBGs into central and peripherally positioned helical cores, while subtracting their characteristics’ wavelengths, allow for unambiguous (temperature and strain compensated) read-out of the fiber’s twist/torsion [79,80] (Figure 14a).

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.


Related in: MedlinePlus