PSI - Issue 33

ScienceDirect StructuralIntegrity Procedia 00 (2021) 000–000 StructuralIntegrity Procedia 00 (2021) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com Sci nceDire t Available online at www.sciencedirect.com ScienceDirect

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

Procedia Structural Integrity 33 (2021) 818–823

© 2021 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 scientific committee of the IGF ExCo Abstract Pentamodes metamaterials, are lattice structures that are used in a wide variety of structures because of their strong-lightweight and negative compressibility. Their lattice nature gives also them an anisotropic behavior. In the new approach in the design of aircrafts structures, it is taken into account the behavior of the structure under damage tolerance. Crack propagation inside materials is considered to be one of the most critical parameters in order to be studied in aircraft structures. Pentamodes as a new type of material, is essential to be examined, their resistance in crack propagation. In this paper a numerical simulation in the case of mode I crack propagation in pentamode structures `is confronted. In addition, a validation of the numerical results with experimental results is going to take place. © 2021 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 Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo Keywords: Pentamodes; crack propagation; finite element method 1. Introduction The resistance in crack propagation of a material is an essential factor in design of mechanical structures. Composite materials and generally advanced materials are under investigation for crack propagation resistance. Pentamodes, part of the metamaterial family, are also under investigation (Fleck et al. (2010), Kadic et al. (2012), Fabbrocino et al. (2015), Amendola et al. (2016), Lymperopoulos et al. (2020)).Their three-dimensional lattice Abstract Pentamodes metamaterials, are lattice structures that are used in a wide variety of structures because of their strong-lightweight and negative compressibility. Their lattice nature gives also them an anisotropic behavior. In the new approach i the design of ircrafts structures, it s taken into ccou t th behavior of the structure under d mage tolera ce. Crack propagation nside materials is considered to be o e of the most critical p rameters in order to be studie in aircraft structures. Pentamodes as a new type of material, is essential t be examined, their resist nc in crack propagation. In this paper a numerical simulati n in the case of m de I cr ck propagation in pentamo e structures `is confronted. In dditio , a validatio of the nu erical results with experimental results is going to tak pl ce. © 2021 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 Statement: Peer-revi w under responsibility of th scientifi committee of the IGF ExCo Keywords: Pentamodes; crack propagation; finite element method 1. Introduction The resistance in crack propagation of a material is an essential factor in design of mechanical structures. Composite materials and generally advanced t i ls are und r nvestigatio for crack propagat on resistance Pentamod s, part of the metamaterial family, are also under investigation (Fleck et al. (2010), Kadic et al. (2012), Fabbrocino et al. (2015), A endol et al. (2016), Lymp opoulos et al. (2020)).Their three-dimensional lattice IGF26 - 26th International Conference on Fracture and Structural Integrity Numerical investigation of pentamodes crack propagation Panagiotis N. Lymperopoulos a, *, Efstathios E. Theotokoglou a, * a Department of Mechanics ,Laboratory of Testing and Materials,School of Applied Mathematical and Physical Sciences, National Technical University of Athens, 5, Heroes of Polytechnion Avenue, Theocaris Building Zografou Campus, PO Box 157 73 Athens, Greece IGF26 - 26th International Conference on Fracture and Structural Integrity Numerical investigation of pentamodes crack propagation Panagiotis N. Lymperopoulos a, *, Efstathios E. Theotokoglou a, * a Department of Mechanics ,Laboratory of Testing and Materials,School of Applied Mathematical and Physical Sciences, National Technical University of Athens, 5, Heroes of Polytechnion Avenue, Theocaris Building Zografou Campus, O Box 157 73 Athens, Greece

* Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: panagiotislymperopoulos@mail.ntua.gr; stathis@central.ntua.gr * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000-0000 . E-mail address: panagiotislymperopoulos@mail.ntua.gr; stathis@central.ntua.gr

2452-3216© 2021 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 Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo 2452-3216© 2021 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 Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo

2452-3216 © 2021 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 scientific committee of the IGF ExCo 10.1016/j.prostr.2021.10.091