PSI - Issue 17

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

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Procedia Structural Integrity 17 (2019) 371–378

ICSI 2019 The 3rd International Conference on Structural Integrity Numerical modeling of the capillary in the Bragg grating area, ensuring uniaxial stress state of embedded fiber-optic strain sensor Grigorii Serovaev a,b* ,Valerii Matveenko b , Natalia Kosheleva a , Andrey Fedorov b ICSI 2019 The 3rd International Conference on Structural Integrity Numerical modeling of the capillary in the Bragg grating area, ensuring uniaxial stress state of embedded fiber-optic strain sensor Grigorii Serovaev a,b* ,Valerii Matveenko b , Natalia Kosheleva a , Andrey Fedorov b

a Perm National Research Polytechnic University, 29 Komsomolsky prospekt, Perm, 614990, Russia b Institute of Continuous Media Mechanics UB RAS, 1, Akademika Koroleva Str, Perm, 614013, Russia a Perm National Research Polytechnic University, 29 Komso olsky prospekt, Perm, 614990, Russia b Institute of Continuous Media Mechanics UB RAS, 1, Akademika Koroleva Str, Perm, 614013, Russia

Abstract Abstract

In this paper, the possibility of providing a uniaxial stress state of FOSS based on the use of a capillary tube in the area of the Bragg grating is studied. The capillary tube, which consists of the additional external coating and a cavity between the coating and the optical fiber, protects the Bragg grating from the effects of transverse strain. This allows to use a direct relation between the measured value of the Bragg wavelength shift and the longitudinal strain. With the help of numerical simulation, the geometric and mechanical parameters of the capillary tube have been studied. Numerical calculations showed a slight effect of the elastic modulus of the capillary coating on the cavity size under load. However, the presence of a cavity in the capillary leads to an increase in stress concentration, which must be considered when designing a capillary tube for a particular application. The obtained results confirmed the effectiveness of the structural scheme of the capillary in the area of FOSS embedded into the controlled material. In this paper, the possibility of providing a uniaxial stress state of FOSS based on the use of a capillary tube in the area of the Bragg grating is studied. The capillary tube, which consists of the additional external coating and a cavity between the coating and t optical fiber, pr tects the Bragg grating from the effects of transverse strain. This allows to use a direct relation between the asured value of the Bragg w velength shift and the longitudinal strain. With the help of numerical simulati n, the geometric and mechanical parameters of the capillary tube have been studied. Numerical cal ulations showed a slight effect of the elastic modulus of the capillary c ating on the cavity size under load. However, the presence of a cavity in the capill ry leads to an increase in stress concentration, which must be considered when designing capillary tube for a particular application. The obtained results confirmed the effectiveness of the structural scheme of the capillary in the area of FOSS embedded into the controlled material.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

Keywords: Fiber optic strain sensor; fiber Bragg grating; capillary; numerical simulation. Keywords: Fiber optic strain sensor; fiber Bragg grating; capillary; numerical simulation.

1. Introduction 1. Introduction

Nowadays, more and more structures are equipped with various sensors, which make it possible to monitor both important operational characteristics and the mechanical state. In the future, the degree of integration of sensing elements will only increase, which changes the design and development approaches and opens fundamentally new Nowadays, more and more structures are equipped with various sensors, which make it possible to monitor both important operational characteristics and the mechanical state. In the future, the degree of integration of sensing elements will only increase, which changes the design and development approaches and opens fundamentally new

* Corresponding author. Tel.: +7(342)2378308. E-mail address: serovaev@icmm.ru * Correspon ing auth r. Tel.: +7(342)2378308. E-mail address: serovaev@icmm.ru

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.049