PSI - Issue 39

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 ScienceDirect Available online at www.sciencedirect.com ScienceDirect

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

Procedia Structural Integrity 39 (2022) 688–699

© 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 Abstract Several recent experimental investigations have clearly demonstrated that the embedding of a little quantity of nanoparticles within the concrete mixture can lead to a notable increase in strength and toughness properties, especially in the case of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC), for which nanoparticles are adopted in a synergistic combination with randomly distributed short-fiber reinforcements. Common fracture and damage models often are not able to capture the complex failure behavior of such structures when subjected to general loadings, which usually promote multiple crack propagation under mixed-mode conditions. In the present work, a crack propagation analysis in nano-enhanced UHPFRC structures is performed, by using a refined diffuse interface approach, according to which a standard finite element mesh is enriched with cohesive interface elements placed along all the internal boundaries and representing potential crack segments. A trilinear traction-separation law has been proposed and properly calibrated to incorporate the toughening effects provided by the embedded nanoparticles. The reliability of the proposed fracture model is assessed by performing complete failure simulations of UHPFRC specimens containing different fractions of nanoparticles (i.e., graphite nanoplatelets) and by comparing the related numerical outcomes with the available experimental data. The present results have shown the numerical accuracy of the proposed approach, also highlighting the role of the embedded nanoparticles in the overall load-bearing capacity as well as in the crack width control for UHPFRC structures. © 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: Crack propagation analysis; Ultra-High-Performance; Nanoparticles; Fiber-Reinforced Concrete. 7th International Conference on Crack Paths Cracking analysis in Ultra-High-Performance Fiber-Reinforced Concrete with embedded nanoparticles via a diffuse interface approach Andrea Pranno a , Fabrizio Greco a* , Lorenzo Leonetti a , Paolo Lonetti a , Paolo Nev ne Blasi a , Umberto De Maio a a Department of Civil Engineering, University of Calabria, Via P. Bucci - Cubo 39B, 87036 Rende (CS), Italy Abstract Several recent experimental investigations have clearly demonstrated that the embedding of a little quantity of nanoparticles within the concret mi ture ca lead to a notable increase in strength an toug ness properties, especially in the c se of Ultra-High Performance Fiber-Reinforced Concrete (UHPFRC), for which nan particles are adopted in a s nergistic combination with rand ly distributed short-fiber reinforcements. Comm n fracture and damage models oft n are not able to apture the complex f ilure behavior of suc structures when subjected to general loadings, which usually promote multiple crack propagation under mixed-mode conditions. In the present work, a crack propag tion analysis in nano-enhanced UHPFRC structures is performed, by using a refined diffuse interface approach, according to which a standard finite element mesh is enriched with cohesive int rface elements placed along all the internal boundaries a d representing potential crack segments. A trili ear traction-separation law has been proposed and properly calibrated t i corpor te th toughening effects provided by the embedded nanoparticl s. The reliability of the proposed fracture model is ssessed by erforming complete failure simulations of UHPFRC specimens containing different fractions of nanoparticles (i.e., graphite nanoplatelets) and by comparing the related numerical outcomes with the available experimental data. The present results have shown the numerical accur cy of the proposed approach, als highlighting the role of the mb dded nanoparticl s i the overall load-bearing capacity as well as in the crack wi th control for UHPFRC structures. © 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: Crack propagation analysis; Ultra-High-Performance; Nanoparticles; Fiber-Reinforced Concrete. 7th International Conference on Crack Paths Cracking analysis in Ultra-High-Performance Fiber-Reinforced Concrete with embedded nanoparticles via a diffuse interface approach Andrea Pranno a , Fabrizio Greco a* , Lorenzo Leonetti a , Paolo Lonetti a , Paolo Nevone Blasi a , Umberto De Maio a a Department of Civil Engineering, University of Calabria, Via P. Bucci - Cubo 39B, 87036 Rende (CS), Italy

* Corresponding author. Tel.: +390984496916; fax: +390984496916. E-mail address: fabrizio.greco@unical.it * Corresponding author. Tel.: +390984496916; fax: +390984496916. E-mail address: fabrizio.greco@unical.it

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

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.2022.03.142