PSI - Issue 18

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

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 18 (2019) 12–19

25th International Conference on Fracture and Structural Integrity Damage detection algorithm based on using surface mounted fiber-optic sensors on Bragg gratings Valerii Matveenko a,b , Natalia Kosheleva b* , Grigorii Serovaev a,b a Institute of Continuous Media Mechanics UB RAS, 1, Akademika Koroleva Str.,Perm, 614013, Russia b Perm National Research Polytechnic University, 29 Komsomolsky prospekt, Perm, Perm krai, 614990, Russia Abstract In the paper the problem associated with the use of fiber-optic strain sensors based on Bragg gratings glued to the surface of the material for the defects registration and their development was studied. The first part of the work is devoted to the numerical and experimental estimation of the error of strain values calculated on the basis of information on physical quantities recorded by sensors. In the second part of the work, a method for defects registration for a given external loads is presented. A background of the technique is the Saint-Venant principle, according to which the change in the strain values with the appearance of a defect occurs in the area defined by 3 – 5 characteristic defect sizes. Based on this, in order to register a defect without preliminary information about the strain distribution, it is necessary to provide in the observed object a strains measurement by the sensors that form a spatial grid with a step of 3 to 5 sizes of the expected defect. Last can be practically unrealistic. In the framework of the considered methodology, based on the results of numerical simulation, the sensors are located in stress concentration zones and areas with moderate stress concentration. Further, in the object without defects on the basis of numerical or experimental data, all variants of the relationships of the strain values obtained by two different sensors are recorded. The change in the monitoring process at least of one of these relationships allows to make a conclusion about the defect appearance as well as its location and evolution. The effectiveness of the technique is illustrated on a sample of a polymer composite material, in which holes of different diameters are made, imitating the appearance and development of a defect. 25th International Conference on Fracture and Structural Integrity Damage detection algorithm based on using surface mounted fiber-optic sensors on Bragg gratings Valerii Matveenko a,b , Natalia Kosheleva b* , Grigorii Serovaev a,b a Institute of Continuous Media Mechanics UB RAS, 1, Akademika Koroleva Str., , 614013, Russia b Perm National Research Polytechnic University, 29 Komsomolsky prospekt, Perm, Perm krai, 614990, Russia Abstract In the paper the problem associated with the use of fib r-optic strain sensors based on Bragg gratings glue t the s rface of the mat rial for the defects registration and their development was studied. The first part of the w rk is devoted to the numerical and experime tal estimation of the error of strain values calculat d on the basis of information n physical quantities recorded by sensors. In the second part of the work, a method for defects registration for a giv n external loads is presented. A background of the tech ique is the Saint-Venant principle, according to which the cha ge in the strain values with the appearance of a defect occurs in the area d fined by 3 – 5 characteristic defect sizes. Based on this, in order to register defect without preliminary information bout the str in distribution, it is necessary to provide in the observed object a strai s measurement by the sensors that form a spatial grid with a step of 3 to 5 sizes of the expected defect. Last can be pr ctically unrealistic. In the fr mework of the considered methodology, based on the results of numerical simulation, the sensors are located in stress concentration zones and areas with moderate stress concentration. Further, in the object ithout d fects on the basis f numerical or experimental data, all variants of the relationships of the strain values obtained by two different sensors are record d. Th change in the monitori g pr cess at least of one of these relationships allows to make a conclusion about the defect appearance as ell as its location and evolution. The effectiveness of the technique is illustrated on a sample of a polymer composite material, in which holes of different diameters are made, imitating the appearance and development of a defect.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

Keywords: fiber-optic sensor; Bragg grating; surface mounted sensor; numerical simulation; experiment; damage detection. Keywords: fiber-optic sensor; Bragg grating; surface mounted sensor; numerical simulation; experiment; damage detection.

* Corresponding author. Tel.: +7(342)2378308. E-mail address: nataly.kosheleva@gmail.com * Correspon ing author. Tel.: +7(342)2378308. E-mail address: nataly.kosheleva@gmail.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.135