{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T07:38:51Z","timestamp":1771918731725,"version":"3.50.1"},"reference-count":17,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,2,19]],"date-time":"2020-02-19T00:00:00Z","timestamp":1582070400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["BI\/UI96\/6642\/2018"],"award-info":[{"award-number":["BI\/UI96\/6642\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["BI\/UI96\/6643\/2018"],"award-info":[{"award-number":["BI\/UI96\/6643\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["PD\/BD\/128265\/2016"],"award-info":[{"award-number":["PD\/BD\/128265\/2016"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["FCT-SFRH\/BD\/146885\/2019"],"award-info":[{"award-number":["FCT-SFRH\/BD\/146885\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/CTM\/50025\/2019"],"award-info":[{"award-number":["UID\/CTM\/50025\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/EMS\/00667\/2019"],"award-info":[{"award-number":["UID\/EMS\/00667\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o","award":["POCI-01-0145-FEDER-016414"],"award-info":[{"award-number":["POCI-01-0145-FEDER-016414"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper focuses on three main issues regarding Material Extrusion (MEX) Additive Manufacturing (AM) of thermoplastic composites reinforced by pre-functionalized continuous Nickel\u2013Titanium (NiTi) wires: (i) Evaluation of the effect of the MEX process on the properties of the pre-functionalized NiTi, (ii) evaluation of the mechanical and thermal behavior of the composite material during usage, (iii) the inspection of the parts by Non-Destructive Testing (NDT). For this purpose, an optical fiber sensing network, based on fiber Bragg grating and a cascaded optical fiber sensor, was successfully embedded during the 3D printing of a polylactic acid (PLA) matrix reinforced by NiTi wires. Thermal and mechanical perturbations were successfully registered as a consequence of thermal and mechanical stimuli. During a heating\/cooling cycle, a maximum contraction of \u2248100 \u00b5m was detected by the cascaded sensor in the PLA material at the end of the heating step (induced by Joule effect) of NiTi wires and a thermal perturbation associated with the structural transformation of austenite to R-phase was observed during the natural cooling step, near 33.0 \u00b0C. Regarding tensile cycling tests, higher increases in temperature arose when the applied force ranged between 0.7 and 1.1 kN, reaching a maximum temperature variation of 9.5 \u00b1 0.1 \u00b0C. During the unload step, a slope change in the temperature behavior was detected, which is associated with the material transformation of the NiTi wire (martensite to austenite). The embedded optical sensing methodology presented here proved to be an effective and precise tool to identify structural transformations regarding the specific application as a Non-Destructive Testing for AM.<\/jats:p>","DOI":"10.3390\/s20041122","type":"journal-article","created":{"date-parts":[[2020,2,20]],"date-time":"2020-02-20T03:20:03Z","timestamp":1582168803000},"page":"1122","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["Embedded Fiber Sensors to Monitor Temperature and Strain of Polymeric Parts Fabricated by Additive Manufacturing and Reinforced with NiTi Wires"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9746-9152","authenticated-orcid":false,"given":"Micael","family":"Nascimento","sequence":"first","affiliation":[{"name":"Department of Physics and i3N, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3749-9186","authenticated-orcid":false,"given":"Patrick","family":"In\u00e1cio","sequence":"additional","affiliation":[{"name":"UNIDEMI, Department of Mechanical and Industrial Engineering, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0736-5849","authenticated-orcid":false,"given":"Tiago","family":"Paix\u00e3o","sequence":"additional","affiliation":[{"name":"Department of Physics and i3N, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"given":"Edgar","family":"Camacho","sequence":"additional","affiliation":[{"name":"CENIMAT\/i3N, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"given":"Susana","family":"Novais","sequence":"additional","affiliation":[{"name":"Department of Physics and i3N, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9072-5010","authenticated-orcid":false,"given":"Telmo","family":"Santos","sequence":"additional","affiliation":[{"name":"UNIDEMI, Department of Mechanical and Industrial Engineering, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"given":"Francisco","family":"Fernandes","sequence":"additional","affiliation":[{"name":"CENIMAT\/i3N, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6002-1060","authenticated-orcid":false,"given":"Jo\u00e3o","family":"Pinto","sequence":"additional","affiliation":[{"name":"Department of Physics and i3N, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,19]]},"reference":[{"key":"ref_1","unstructured":"Patrick, L.I., Camacho, E., Rodrigues, P.F., Miranda, R.M., Velhinho, A., Braz Fernandes, F.M., and Santos, T.G. (2018, January 11\u201315). Evaluation of functionally graded Ni-Ti wires for additive manufacturing of composites. Proceedings of the 12th European Conference on Non-Destructive Testing (ECNDT2018), Gothenburg, Sweden."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"125015","DOI":"10.1088\/0964-1726\/22\/12\/125015","article-title":"Structural health monitoring of an asymmetrical SMA reinforced composite using embedded FBG sensors","volume":"22","author":"Ho","year":"2013","journal-title":"Smart Mater. Struct."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3907","DOI":"10.1007\/s00707-015-1433-0","article-title":"Review and Perspectives: Shape Memory Alloy Composite Systems","volume":"226","author":"Lester","year":"2015","journal-title":"Acta Mech."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"105010","DOI":"10.1088\/0964-1726\/21\/10\/105010","article-title":"Multifunctional SMArt composite material for in situ NDT\/SHM and de-icing","volume":"21","author":"Pinto","year":"2012","journal-title":"Smart Mater. Struct."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1007\/s13320-012-0094-z","article-title":"Structural health monitoring of different geometry structures with optical fiber sensors","volume":"2","author":"Antunes","year":"2012","journal-title":"Photonic Sens."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"102015","DOI":"10.1016\/j.yofte.2019.102015","article-title":"Embedding optical fiber Bragg grating (FBG) sensors in 3D printed casings","volume":"53","author":"Manzo","year":"2019","journal-title":"Opt. Fiber Technol."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Santos, J.L., and Farahi, F. (2015). Handbook of Optical Sensors, CRC Press.","DOI":"10.1201\/b17641"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"28353","DOI":"10.1364\/OE.20.028353","article-title":"High-sensitivity ultrasonic phase-shifted fiber Bragg grating balanced sensing system","volume":"20","author":"Wu","year":"2012","journal-title":"Opt. Express"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Grattan, K.T., and Meggitt, B.T. (1999). Optical fiber sensor technology (Volume 2: Optoelectronics, Imaging and Sensing Series), Kluwer Academic Publishers.","DOI":"10.1007\/978-94-017-2484-5"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Nascimento, M., Ferreira, M.S., and Pinto, J.L. (2018). Simultaneous Sensing of Temperature and Bi-Directional Strain in a Prismatic Li-Ion Battery. Batteries, 4.","DOI":"10.3390\/batteries4020023"},{"key":"ref_11","first-page":"25242","article-title":"Fiber Bragg gratings embedded in 3D printed prototypes","volume":"2","author":"Homa","year":"2016","journal-title":"Sci. Adv. Today"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jpowsour.2018.10.096","article-title":"Internal strain and temperature discrimination with optical fiber hybrid sensors in Li-ion batteries","volume":"410","author":"Nascimento","year":"2019","journal-title":"J. Power Sources"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"115025","DOI":"10.1088\/1361-665X\/aa91ab","article-title":"Simultaneous strain and temperature measurement using a single fiber Bragg grating embedded in a composite laminate","volume":"26","author":"Singh","year":"2017","journal-title":"Smart Mater. Struct."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Zubel, M.G., Sugden, K., Webb, D.J., Saez-Rodriguez, D., Nielsen, K., and Bang, O. (2016, January 27). Embedding silica and polymer fibre Bragg gratings (FBG) in plastic 3D-printed sensing patches. Proceedings of the SPIE 9886, Micro-Structured and Specialty Optical Fibres IV, Brussels, Belgium.","DOI":"10.1117\/12.2228753"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1088\/0957-0233\/8\/4\/002","article-title":"In-fibre Bragg grating sensors","volume":"8","author":"Rao","year":"1997","journal-title":"Meas. Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"113872","DOI":"10.1016\/j.applthermaleng.2019.113872","article-title":"Simulation and validation of thermography inspection for components produced by additive manufacturing","volume":"159","author":"Carvalho","year":"2019","journal-title":"Appl. Therm. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1033","DOI":"10.1364\/AO.51.001033","article-title":"Microbubble based fiberoptic Fabry\u2013Perot interferometer formed by fusion splicing single-mode fibers for strain measurement","volume":"51","author":"Duan","year":"2012","journal-title":"Appl. Opt."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/4\/1122\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:58:55Z","timestamp":1760173135000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/4\/1122"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,19]]},"references-count":17,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["s20041122"],"URL":"https:\/\/doi.org\/10.3390\/s20041122","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,19]]}}}