Issue 51

G.S. Serovaev et alii, Frattura ed Integrità Strutturale, 51 (2020) 225-235; DOI: 10.3221/IGF-ESIS.51.18 225 Focussed on IGF25 – Fracture and Structural Integrity International Conference 2019 The study of internal structure of woven glass and carbon fiber reinforced composite materials with embedded fiber-optic sensors Grigorii S. Serovaev Institute of Continuous Media Mechanics UB RAS, Russian Federation serovaev@icmm.ru, http://orcid.org/0000-0003-0312-8088 Natalia A. Kosheleva Institute of Continuous Media Mechanics UB RAS, Russian Federation kosheleva.n@icmm.ru, http://orcid.org/0000-0002-8760-2957 A BSTRACT . In this work, samples from composite materials with embedded optical fibers are investigated. It is known that for unidirectional layered composite materials a distortion of the internal structure and the formation of such technological defect as resin pocket in the region of the embedded optical fiber occur under certain conditions. So it is important to evaluate the change in the internal structure for other types of reinforcement, in particular, woven reinforcement. Analysis of the internal structure of the studied materials with 2  2 twill weave style was carried out using a digital microscope. In addition, the reflected optical signal from the Bragg gratings after being embedded into the composite material is analyzed. K EYWORDS . Polymer composite material; Woven reinforcement; Single- mode optical fiber; FBG; Sensor embedded in the material. Citation: Serovaev, G., Kosheleva, N., The study of internal structure of woven glass and carbon fiber reinforced composite materials with embedded fiber-optic sensors, Frattura ed Integrità Strutturale, 51 (2020) 225-235. Received: 06.11.2019 Accepted: 24.11.2019 Published: 01.01.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ith the constant increase in the use of composite materials in the industry, the share of so-called “smart materials” is also increasing today. Such materials are equipped with different sensing elements which give them the ability to sense the changes of the environmental conditions and to assess their mechanical state and even react to these changes. Among the most promising are the fiber-optic sensors which in combination with widely spread composite materials open new prospects in design and manufacturing of objects of various types of purposes. Thus, it becomes possible to monitor such parameters as strain, temperature and other parameters related to structural health monitoring. The embedded optical fibers and related technological defects can negatively influence the overall strength and stiffness of the controlled object and can cause dangerous local stress and strain concentrations. According to the known studies, influence of embedded optical fibers varies significantly for different kinds of composite materials, types of external loading, orientation of embedded optical fiber to reinforcing fibers and to the direction of loading. Under static loads an W