PSI - Issue 24

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 ScienceDirect Available onlin at www.sci n edirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

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Procedia Structural Integrity 24 (2019) 259–266

© 2019 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 AIAS2019 organizers © 2019 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 AIAS2019 organizers The identification of the above features and their implementation in the thermal softening from static tests can also help in correctly assessing the strain rate sensitivity of materials from dynamic tests by Hopkinson bar, where the thermal and dynamical effects are intrinsically coupled to each other and a procedure for their separate assessment is not yet standardised. © 2019 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 AIAS2019 organizers The thermal softening has been recently demonstrated to directly depend also on the plastic strain other than depending on the temperature, so that the stress-strain curves of a metal at different constant temperatures are not proportional each other through a single, temperature-dependent scale factor. In this paper a considerable anticipation of the necking onset from static tests at increasing constant temperatures is highlighted for a stainless steel, which directly delivers further evidence that the thermal softening depends on both temperature and strain. Only in the post-necking ranges the strain seems to not influence the thermal softening anymore. Also, the variabilities of temperature and strain rate during dynamic strain histories are shown to further affect the necking onset, while an ideally constant high strain rate does not. The identification of the above features and their implementation in the thermal softening from static tests can also help in correctly assessing the strain rate sensitivity of materials from dynamic tests by Hopkinson bar, where the thermal and dynamical effects are intrinsically coupled to each other and a procedure for their separate assessment is not yet standardised. Abstract The thermal softening has been recently demonstrated to directly depend also on the plastic strain oth than dependin on the temperature, so that t e str ss-strain curves of a metal at different const nt temperatures are not proportional each other through a singl , temp rature-dependent c le factor. In this paper a considerable anticipatio of the ecking o set fro static tests at incre sing constant temperatures is highlighted for a stainless steel, which directly delivers further evidence that the thermal softening depends on both temperature and strain. Only in the post-necki g ranges the str in seems to not influence the thermal softening anymore. Also, the variabilities of temperature and strain ate uring dynamic strain hi t ries are shown to further affect the necking onset, while an ideally constant high strain rate d es not. Keywords: Necking; Tensile instability; Steel; Temperature; Strain Rate; Thermal Softening. AIAS 2019 International Conference on Stress Analysis Coupling of temperature and strain in thermal softening of a stainless steel at low and high strain rates Giuseppe Mirone*, Raffaele Barbagallo University of Catania, DICAR - Department of Civil Engineering and Architecture, Via Santa Sofia 64 – 95125 – Catania, Italy AIAS 2019 Internatio al Conference on Stress Analysis Coupling of temperature and strain in thermal softening of a stainless steel at low and high strain rates Giuseppe Mirone*, Raffaele Barbagallo University of Catania, DICAR - Department of Civil Engineering and Architecture, Via Santa Sofia 64 – 95125 – Catania, Italy Abstract

Keywords: Necking; Tensile instability; Steel; Temperature; Strain Rate; Thermal Softening.

* Corresponding author. Tel.: +39 095 738 2418. E-mail address: gmirone@dii.unict.it

2452-3216 © 2019 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 AIAS2019 organizers 2452-3216 © 2019 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 AIAS2019 organizers * Corresponding author. Tel.: +39 095 738 2418. E-mail address: gmirone@dii.unict.it

2452-3216 © 2019 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 AIAS2019 organizers 10.1016/j.prostr.2020.02.023