PSI - Issue 28

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

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

Procedia Structural Integrity 28 (2020) 608–618

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo Abstract The problem of thermal fracture of a structure consisting of a functionally graded coating (FGC) on a homogeneous substrate (FGC/H) subjected to a thermal loading is investigated. The main focus is laid on the application of fracture criteria for an FGC and the determination of critical mechanical and thermal loads. The application of fracture criteria requires knowledge of the fracture toughness near the crack tips. Thus, it is assumed that the fracture toughness of an FGC, as well as other material properties, continuously varies through the thickness of the coating. Besides, having a system of cracks, it is important to determine which crack is most dangerous with respect to possible propagation. The proposed model, combined with a detailed parametric analysis, provides a reliable basis for optimizing FGCs in order to improve the fracture resistance of FGC/homogeneous systems operating under high temperatures. An illustrative example for a real combination of materials (ceramic/metal)/metal is provided, which demonstrates that it is important to consider the variation of fracture toughness in FGCs in determining critical loads at which cracks can lead to complete structural fracture. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo Keywords : Thermal fracture; system of cracks; functionally graded coatings; fracture criteria 1. Introduction Functionally graded materials (FGMs) represent a concept for composites that consist of a graded pattern of material composition and/or microstructures and, accordingly, with properties continuously graded in the same spatial 1st Virtual European Conference on Fracture Analysis of interacting cracks in functionally graded thermal barrier coatings Vera Petrova a,b, *,Siegfried Schmauder a a IMWF, University of Stuttgart, Pfaffenwaldring 32, Stuttgart 70569, Germany b Voro ezh State University, Univ rsity Sq.1, Voronezh 394 0 , Russia Abstract The problem of thermal fracture of a structure consisting of a functionally graded coating (FGC) on a homogeneous substrate (FGC/H) subjected to thermal l ading is inv stigated. The main focus is laid on the pplication of fracture criteria for an FGC and the determination of c itical mechanical and thermal loads. The applicati of fracture criteria eq ir s knowledge of the fractur toughness near the cra k tips. Thus, it is assumed that the fracture toughness an FGC, as well as other material properties, con inuously varies th ough the hickness of the coating. Besides, having a system of cracks it is important to d termine which rack is most d ngerous with r spe t to possibl pr pagation. The proposed mod l, c mbined with a detailed param tric analysis, p ovides a reliable basi for optimizing FGCs in o der to mprov the fracture resistance of FGC/ omogen ous syst ms operating under high temp ratures. An illustrative example fo a real c mbination of materi ls (ceramic metal)/m tal i provided, wh ch demonstrates that it is important to consider the variation of fracture t ughness in FGCs in determining crit cal l ads at cracks can lead to complete s ructural fractu e. © 2020 The Au hors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integri y Soci ty (ESIS) ExC K ywords : Thermal fracture; system of cracks; functionally graded coatings; fracture criteria 1. Introduction Functionally graded materials (FGMs) represent a concept for composites that consist of a graded pattern of material compositi and/or microstructures and, accordingly, wi h pr perties continu usly gr ded in the same spat 1st Virtual European Conference on Fracture Analysis of interacting cracks in functionally graded thermal barrier coatings Vera Petrova a,b, *,Siegfried Schmauder a a IMWF, University of Stuttgart, Pfaffenwaldring 32, Stuttgart 70569, Germany b Voronezh State University, University Sq.1, Voronezh 394006, Russia

* Corresponding author. Tel.: +49-711-685-63339; fax:+49-711-685-67779. E-mail address: vera.petrova@imwf.uni-stuttgart.de;veraep@gmail.com * Corresponding author. Tel.: +49-711-685-63339; fax:+49-711-685-67779. E-mail address: vera.petrova@imwf.uni-stuttgart.de;veraep@gmail.com

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review u der responsibility of t European Structural Integrity So i ty (ESIS) ExCo

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.071