PSI - Issue 39

Andrea Pranno et al. / Procedia Structural Integrity 39 (2022) 688–699 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig 8. Deformed configuration and stress color map for the investigated UHPFRC beams at a load level equal to 65 kN.

Conclusions In this work, the effect of the incorporation of graphite nanoplatelets (GNPs) on the load-carrying capacity of steel reinforced UHPFRC beams has been investigated. With reference to simply supported beams subjected to a four-point bending test, the cracking failure analyses have been performed to study the role of the embedded nanoparticles in the overall load-bearing capacity as well as in the crack width control for UHPFRC structures at different loading stages. The numerical results have been validated through comparisons with experimental results and a good agreement between the numerical and experimental loading curves has been found. The proposed computational model resulted to be accurate and reliable in predicting the strengthening effect on the global load-deflection response which was obtained by incorporating graphene nanoparticles in the UHPFRC beams. Specifically, the addition of 0.1% of volume fraction increased the first yielding load level of about 11% and the absorbed energy up to 20%. In addition, at a given loading stage, the crack patterns and associated stress distribution maps have been analyzed and an increase of the bending stiffness and a reduction of the average crack width and crack spacing were highlighted with the addition of 0.05% and 0.1% of graphene nanoplatelets, respectively. As future perspectives, the main idea is to adopt the proposed numerical model in investigating more complex failure mechanisms involving buildings and bridge structural elements (Lonetti and Pascuzzo (2020), (2016)) giving the opportunity to adopt more accurate designing procedures (Lonetti et al. (2019); Lonetti and Pascuzzo (2014), Bruno et al. (2016)) for civil structures characterized by the employment of new advanced materials. However, the case of modeling the failure processes in buildings and bridge structural elements could lead to huge computational efforts which can be reduced by incorporating such numerical framework in a more advanced numerical framework based on the homogenization techniques (Greco et al. (2018a), (2018b); Maio et al. (2020); Greco et al. (2021b)) and multiscale methodologies (Greco et al. (2020b), (2020a), (2020c)) as already proposed by some of the authors for fiber- and particle-reinforced composite materials. Acknowledgements Fabrizio Greco and Paolo Lonetti gratefully acknowledge financial support from the Italian Ministry of Education, University and Research (MIUR) under the P.R.I.N. 2017 National Grant “Multiscale Innovative Materials and