PSI - Issue 80

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 80 (2026) 256–268 Structural Integrity Procedia 00 (2022) 000 – 000

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

© 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 Ferri Aliabadi This study develops a numerical model to predict the stiffness of lattice struts produced by FFF, considering the complex interactions among three phases: filaments, pores, and bonding (intersection) regions. The model integrates geometric and morphological aspects of porosity and inter-filament connections within a representative volume framework, enabling the prediction of effective elastic moduli under various deposition configurations. This approach highlights the critical role of filament intersections and bonding morphology in determining the overall mechanical response of FFF lattice structures. Keywords: Fused Filament Fabrication; filament porosity; Inter-filament bonding; Numerical modeling; Homogenization; Elastic properties; Lattice struts This study develops a numerical model to predict the stiffness of lattice struts produced by FFF, considering the complex interactions among three phases: filaments, pores, and bonding (intersection) regions. The model integrates geometric and morphological aspects of porosity and inter-filament connections within a representative volume framework, enabling the prediction of effective elastic moduli under various deposition configurations. This approach highlights the critical role of filament intersections and bonding morphology in determining the overall mechanical response of FFF lattice structures. Keywords: Fused Filament Fabrication; filament porosity; Inter-filament bonding; Numerical modeling; Homogenization; Elastic properties; Lattice struts Fracture, Damage and Structural Health Monitoring Modeling of Mechanical Behavior in FFF Lattice Struts: Integrating Porosity and Inter-Filament Bonding R.Salem a,b , F.Barbe a , I.Benedetti b* a Groupe de Physique des Matériaux, UMR CNRS 6634, Normandie Université, INSA Rouen, Univ. Rouen, 76000 Rouen, France b Department of Engineering, University of Palermo, Viale delle Scienze, Edificio 8, Palermo, 90128, Italy Abstract Fused Filament Fabrication (FFF) is an additive manufacturing process that constructs three-dimensional structures through the sequential deposition of thermoplastic filaments. This process inherently produces anisotropic porosity networks, shaped by the filament deposition paths and the formation of bonding regions between adjacent filaments. In thin structural elements such as lattice struts, where dimensions are comparable to filament diameters, these microstructural features have a pronounced effect on the mechanical behavior. In particular, regions of inter filament bonding, where polymer chain interdiffusion occurs, introduce distinct mechanical characteristics beyond those captured by porosity volume alone. Fracture, Damage and Structural Health Monitoring Modeling of Mechanical Behavior in FFF Lattice Struts: Integrating Porosity and Inter-Filament Bonding R.Salem a,b , F.Barbe a , I.Benedetti b* a Groupe de Physique des Matériaux, UMR CNRS 6634, Normandie Université, INSA Rouen, Univ. Rouen, 76000 Rouen, France b Department of Engineering, University of Palermo, Viale delle Scienze, Edificio 8, Palermo, 90128, Italy Abstract Fused Filament Fabrication (FFF) is an additive manufacturing process that constructs three-dimensional structures through the sequential deposition of thermoplastic filaments. This process inherently produces anisotropic porosity networks, shaped by the filament deposition paths and the formation of bonding regions between adjacent filaments. In thin structural elements such as lattice struts, where dimensions are comparable to filament diameters, these microstructural features have a pronounced effect on the mechanical behavior. In particular, regions of inter filament bonding, where polymer chain interdiffusion occurs, introduce distinct mechanical characteristics beyond those captured by porosity volume alone.

* Corresponding author. Tel.: +3909123896728 E-mail address: ivano.benedetti@unipa.it

* Corresponding author. Tel.: +3909123896728 E-mail address: ivano.benedetti@unipa.it 2452-3216

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 Ferri Aliabadi 10.1016/j.prostr.2026.02.025 © 2023 The Authors. Published by ELSEVIER B.V.This is an open access article under the CC BY-NC-ND license (HYPERLINK "https://creativecommons.org/licenses/by-nc-nd/4.0" \t "_blank"https://creativecommons.org/licenses/by-nc-nd/4.0)Peer-review under responsibility of Professor Ferri Aliabadi © 2023 The Authors. Published by ELSEVIER B.V.This is an open access article under the CC BY-NC-ND license (HYPERLINK "https://creativecommons.org/licenses/by-nc-nd/4.0" \t "_blank"https://creativecommons.org/licenses/by-nc-nd/4.0)Peer-review under responsibility of Professor Ferri Aliabadi 2452-3216