PSI - Issue 25

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ScienceDirect

Procedia Structural Integrity 25 (2020) 172–179 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

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© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers Abstract The seismic protection of buildings is a key part of the design of modern buildings. The use of existing seismic wave absorption devices are experiencing ageing problems over the years. For this reason, various alternative configurations, behaving as isolators have been proposed, including the use of metamaterials type of pentamodes. The aim of this work is to study the pentamodes regarding their use in various applications and particularly for the anti seismic design. Therefore, at first, an analytical approach of metamaterials, in static problems is presented. Results are then presented through the use of finite elements for various types of boundary conditions and for three di ff erent materials used in metamaterials systems. From our analysis, it can be concluded the optimum dimensions of the pentamode rod in order to have similar behaviour with isolators. Moreover, the pentamodes configu ration which are made with metallic materials result that their use should be applied in the seismic protection design and aircraft structures, while the pentamodes which are manufactured from polymers are preferable to be used in applications of biomechanics. c 2020 The Authors. Published by Elsevier B.V. T is is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) r-review lin : Peer-rev ew und r responsibility of the VCSI1 organizers. Keywords: Metamaterials; Pentamode; Finite Elements Analysis; Composite Materials; Biomechanics 1st Virtual Conference on Structural Integrity – VCSI1 Computational analysis of metamaterials - an initial study P. N. Lymperopoulos a, ∗ , E. E. Theotokoglou a, ∗ , I. A. Antoniadis b a School of Applied Mathematical and Physical Sciences Department of Mechanics Laboratory of Testing and Materials National Technical University of Athens Zographou Campus, Theocaris Bld, GR-157 73, Athens, Greece b School of Mechanical Engineering, Section of Mechanical Design & Automatic Control, National Technical University of Athens, Zographou Campus, E Bld, GR-157 73, Athens, Greece Abstract The seismic protection of buildings is a key part of the design of modern buildings. The use of existing seismic wave absorption devices are experiencing ageing problems over the years. For this reason, various alternative configurations, behaving as isolators have been proposed, including the use of metamaterials type of pentamodes. The aim of this work is to study the pentamodes regarding their use in various applications and particularly for the anti seismic design. Therefore, at first, an analytical approach of metamaterials, in static problems is presented. Results are then presented through the use of finite elements for various types of boundary conditions and for three di ff erent materials used in metamaterials systems. From our analysis, it can be concluded the optimum dimensions of the pentamode rod in order to have similar behaviour with isolators. Moreover, the pentamodes configu ration which are made with metallic materials result that their use should be applied in the seismic protection design and aircraft structures, while the pentamodes which are manufactured from polymers are preferable to be used in applications of biomechanics. c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the VCSI1 organizers. Keywords: Metamaterials; Pentamode; Finite Elements Analysis; Composite Materials; Biomechanics 1st Virtual Conference on Structural Integrity – VCSI1 Computational analysis of metamaterials - an initial study P. N. Lymperopoulos a, ∗ , E. E. Theotokoglou a, ∗ , I. A. Antoniadis b a School of Applied Mathematical and Physical Sciences Department of Mechanics Laboratory of Testing and Materials National Technical University of Athens Zographou Campus, Theocaris Bld, GR-157 73, Athens, Greece b School of Mechanical Engineering, Section of Mechanical Design & Automatic Control, National Technical University of Athens, Zographou Campus, E Bld, GR-157 73, Athens, Greece

1. Introduction 1. Introduction

Metamaterials is a subset of a broader family of materials, the Composite Materials, and they are designed to have properties that are not found in materials in nature. (p.s. negative Poisson ratio or negative electric and magnetic coeficient). Metamaterials have been theoretically studied from the beginning of the 19 th century. First implementation of metamaterials appears on aircrafts’ antennas (Capolino F. (2009)). According to wave theory, the antenna’s length should be several meters which is unacceptable for the size of an aircraft. The usage of metamaterials has contribute to reduce the size of antennas, in a strictly defined band . Metamaterials is a subset of a broader family of materials, the Composite Materials, and they are designed to have properties that are not found in materials in nature. (p.s. negative Poisson ratio or negative electric and magnetic coeficient). Metamaterials have been theoretically studied from the beginning of the 19 th century. First implementation of metamaterials appears on aircrafts’ antennas (Capolino F. (2009)). According to wave theory, the antenna’s length should be several meters which is unacceptable for the size of an aircraft. The usage of metamaterials has contribute to reduce the size of antennas, in a strictly defined band .

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 10.1016/j.prostr.2020.04.020 ∗ Corresponding authors E-mail address: panaglib@gmail.com; stathis@central.ntua.gr 2210-7843 c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the VCSI1 organizers. ∗ Corresponding authors E-mail address: panaglib@gmail.com; stathis@central.ntua.gr 2210-7843 c 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review line: Peer-review under responsibility of the VCSI1 organizers.