PSI - Issue 68

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 68 (2025) 922–928

European Conference on Fracture 2024 The effect of infill density on fracture toughness results of PLA material Aleksa Milovanović a, *, Tomáš Babinský b , Aleksandar Sedmak c , Ivana Filipović a , Miloš Milošević a a University of Belgrade, Innovation Center of The Faculty of Mechanical Engineering, Kraljice Marije 16 Street, Belgrade 11120, Serbia b Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, Brno 61662, Czech Republic c University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16 Street, Belgrade 11120, Serbia Abstract The main objective of this research is to obtain a comprehensive insight into the influence of infill density on the fracture toughness results of PLA material, used in FDM technology. This paper presents four infill cases (100%; 70%; 40%; 10%) with 0.1 mm layer height. The whole research includes cases from 10 to 100% infill with a 10% increment on three different layer heights (0.3; 0.2; 0.1 mm). The FDM-grade PLA material is brittle hence, the fracture toughness of this material was estimated using the ASTM D5045-14 standard on SENB specimen geometry. This standard requires the plane-strain state near the crack tip to be met to obtain valid results. Three specimens were tested per infill group, all of which met the plane-strain condition. However, when looking at the K IC results from the highest to the lowest infill in all three considered layer configurations, the SENBs start to fail at 50%- onward due to the apparent presence of plasticity. This is evident from the maximum load value in the lower infill cases, where it exceeds the conditional value by more than the limit value of 10%. Therefore, for a better assessment of current results, the J integral approach was also used. © 2025 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) © 2025 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 ECF24 organizers

Peer-review under responsibility of ECF24 organizers Keywords: PLA; infill density; fracture toughness; J-integral.

* Corresponding author. Tel.: +381-64-614-8698. E-mail address: amilovanovic@mas.bg.ac.rs

2452-3216 © 2025 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 ECF24 organizers

2452-3216 © 2025 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 ECF24 organizers 10.1016/j.prostr.2025.06.151