{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T19:48:31Z","timestamp":1775504911402,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,3,31]],"date-time":"2021-03-31T00:00:00Z","timestamp":1617148800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Seventh Framework Programme","award":["619205"],"award-info":[{"award-number":["619205"]}]},{"DOI":"10.13039\/501100004343","name":"Stavros Niarchos Foundation","doi-asserted-by":"publisher","award":["ARCHERS"],"award-info":[{"award-number":["ARCHERS"]}],"id":[{"id":"10.13039\/501100004343","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Belgian Science Policy Interuniversity Attraction Pole","award":["P7\/35."],"award-info":[{"award-number":["P7\/35."]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this study, silica glass, optical fiber Bragg gratings (FBGs) are used for torque-induced strain monitoring in carbon fiber reinforced polymer (CFRP) hollow shafts toward the development of a methodology for structural load monitoring. Optical fibers with gratings are embedded during shaft manufacturing, by an industrial filament winding process, along different orientations with respect to its central axis and surface mounted after production. Experimental results are supported by numerical modeling of the shaft with appropriate boundary conditions and homogenized material properties. For an applied torque up to 800 Nm, the strain sensitivity of an embedded grating positioned along the reinforcing fibers\u2019 direction winded under 55\u00b0 is in the order of 3.6 pm\/Nm, while this value is more than 4\u00d7 times higher than the other examined orientations. The study also shows that surface-mounted optical fiber Bragg gratings along the reinforcing carbon fibers\u2019 direction perform equally well in monitoring strains in composite shafts under torque.<\/jats:p>","DOI":"10.3390\/s21072403","type":"journal-article","created":{"date-parts":[[2021,3,31]],"date-time":"2021-03-31T05:57:18Z","timestamp":1617170238000},"page":"2403","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Monitoring of Torque Induced Strain in Composite Shafts with Embedded and Surface-Mounted Optical Fiber Bragg Gratings"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4967-7197","authenticated-orcid":false,"given":"Maria","family":"Konstantaki","sequence":"first","affiliation":[{"name":"Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion, 70013 Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Georgios","family":"Violakis","sequence":"additional","affiliation":[{"name":"Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion, 70013 Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1570-6885","authenticated-orcid":false,"given":"Georgios A.","family":"Pappas","sequence":"additional","affiliation":[{"name":"Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL), LMAF, STI, CH-1015 Lausanne, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8195-8071","authenticated-orcid":false,"given":"Thomas","family":"Geernaert","sequence":"additional","affiliation":[{"name":"Brussels Photonics (B-PHOT), Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4170-6133","authenticated-orcid":false,"given":"Nikos","family":"Korakas","sequence":"additional","affiliation":[{"name":"Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion, 70013 Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nikos","family":"Tiriakidis","sequence":"additional","affiliation":[{"name":"BT Composites S. A., 53100 Florina, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomai","family":"Tiriakidi","sequence":"additional","affiliation":[{"name":"BT Composites S. A., 53100 Florina, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kosmas","family":"Tiriakidis","sequence":"additional","affiliation":[{"name":"BT Composites S. A., 53100 Florina, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0483-0960","authenticated-orcid":false,"given":"Hugo","family":"Thienpont","sequence":"additional","affiliation":[{"name":"Brussels Photonics (B-PHOT), Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0822-233X","authenticated-orcid":false,"given":"Francis","family":"Berghmans","sequence":"additional","affiliation":[{"name":"Brussels Photonics (B-PHOT), Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John","family":"Botsis","sequence":"additional","affiliation":[{"name":"Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL), LMAF, STI, CH-1015 Lausanne, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4842-1328","authenticated-orcid":false,"given":"Stavros","family":"Pissadakis","sequence":"additional","affiliation":[{"name":"Foundation for Research and Technology-Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), Heraklion, 70013 Crete, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,31]]},"reference":[{"key":"ref_1","unstructured":"Chung, D.D.L. 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