Bioinspired optical fiber sensor for simultaneous shear and vertical forces monitoring

Cátia Tavares, M. Fátima Domingues, Nélia Alberto, António Ramos, Eduardo Rocon, Paulo André, Hugo Silva, Paulo Antunes

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


This work reports the development of a bioinspired sensor capable of measuring vertical and shear (tangential) forces. The sensor is composed of two materials, the polylactide (PLA) and epoxy resin, combined with a photosensitive optical fiber with two fiber Bragg gratings (FBG1 and FBG2). The FBG1 was placed in a cavity filled with epoxy resin, while FBG2 was between the cavity and the shear wall that undergoes shear force. This FBGs’ encapsulation allowed one of them to be affected by vertical and shear forces (FBG1), while FBG2 was only affected by shear force. The calibration and performance tests were carried out with the aid of an electronic tri-axial force sensor. From these tests, sensitivities of K1V= 0.02±2.35x10-4 nm/N; K1S= 0.13±3.25x10-3 nm/N; K2V= -2.88x10-4±6.72x10-5 nm/N and K2S= -1.77±0.03 nm/N to each type of force, for FBG1 and FBG2, respectively, were achieved. The obtained results demonstrated the reliability of the developed solution, with a significant improvement of its sensitivity to shear force, and a low production complexity, when compared to other previously reported optical sensors.

Original languageBritish English
Title of host publicationOptical Sensors 2019
EditorsFrancesco Baldini, Jiri Homola, Robert A. Lieberman
ISBN (Electronic)9781510627222
StatePublished - 2019
EventOptical Sensors 2019 - Prague, Czech Republic
Duration: 1 Apr 20194 Apr 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Sensors 2019
Country/TerritoryCzech Republic


  • Bioinspired optical fiber sensor
  • Fiber Bragg grating
  • Shear force sensor
  • Vertical force sensor


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