PSI - Issue 39

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Procedia Structural Integrity 39 (2022) 34–40

7th International Conference on Crack Paths Fatigue crack growth in the re-entrant auxetic structure Branko Nečemer a *, Janez Kramberger a , Srečko Glodež a a University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor, Slovenia 7th International Conference on Crack Paths Fatigue crack growth in the re-entrant auxetic structure Branko Nečemer a *, Janez Kramberger a , Srečko Glodež a a University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor, Slovenia

© 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 CP 2021 – Guest Editors © 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 CP 2021 – Guest Editors Keywords: Re-entrant auxetic structure; Fatigue behaviour; Experimental testing; Computational analyses Abstract The investigation f fatigue b h viour of the re-e trant and rotated re- ntrant auxetic spe i ens made of Al- lloy 7075-T651 s presented in this study. In the proposed work, th influence of th o ientatio of the nit cell on the crack p h and fatigue life studied by using both experimental an computat onal approac s. In th experimental and computational approach, two geometric layouts of the base unit cell wer analys d (re-entrant and ro ated re-entrant structure). The Low Cycle Fatigu (LCF) tests e e performed at load control with the l ad ratio 0.1 in t nsile. In the LCF tests, f v loading level w re selected and at least two tests were performed at each lo ding level. The same loading conditions w re then appl ed in the computational model in the framework of the ANSYS software package. For the fatigue life calculation, the strain life approach was used, based on the Coffin-Manson model with a Morrow mean stress correction. The comparison between computational and experimental results regarding − fatigue-life curves and observed fatigue failure path showed a reasonable agreement. © 2021 The Autho s. Publ shed by ELSEVIER B.V. This is an ope access article nd r the CC BY-NC-ND license (https://creativecommo s.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of CP 2021 – Guest Editors Keywords: Re-entrant auxetic structure; Fatigue behaviour; Experimental testing; Computational analyses Abstract The investigation of fatigue behaviour of the re-entrant and rotated re-entrant auxetic specimens made of Al-alloy 7075-T651 is presented in this study. In the proposed work, the influence of the orientation of the unit cell on the crack path and fatigue life were studied by using both experimental and computational approaches. In the experimental and computational approach, two geometric layouts of the base unit cell were analysed (re-entrant and rotated re-entrant structure). The Low Cycle Fatigue (LCF) tests were performed at load control with the load ratio 0.1 in tensile. In the LCF tests, five loading levels were selected and at least two tests were performed at each loading level. The same loading conditions were then applied in the computational model in the framework of the ANSYS software package. For the fatigue life calculation, the strain life approach was used, based on the Coffin-Manson model with a Morrow mean stress correction. The comparison between computational and experimental results regarding − fatigue-life curves and observed fatigue failure path showed a reasonable agreement.

* Corresponding author. Tel.: +386-2-220-7832; fax: +386-2-220-7994. E-mail address: branko.necemer@um.si

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 CP 2021 – Guest Editors 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 CP 2021 – Guest Editors * Corresponding author. Tel.: +386-2-220-7832; fax: +386-2-220-7994. E mail address: branko.necemer@um.si

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 CP 2021 – Guest Editors 10.1016/j.prostr.2022.03.069