PSI - Issue 68

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 68 (2025) 59–65

European Conference on Fracture 2024 Water diffusion in additively manufactured polymers: effect of capillary shapes Boyu Li, Konstantinos P. Baxevanakis*, and Vadim V. Silberschmidt Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, LE11 3TU, UK

© 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 Abstract Additive manufacturing (AM) is an advanced manufacturing technique that produces objects through sequential layering. However, defects generated during such manufacturing lead to a complex internal structure in 3D-printed polymers, resulting in unique micro mechanisms governing water diffusion. The effects of exposure to water on the mechanical properties of AM materials remain insufficiently understood. Recent studies acknowledged the impact of capillary flow penetrating the polymer; however, most of this research is performed at the macroscale. This study aims to explore the effect of capillary shape on the speed and range of the capillary flow. A constitutive model, derived from the previous numerical studies, is adapted to various capillary geometries. It is demonstrated that the shape significantly affects the penetration speed and distance of capillary flow. © 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 Keywords: additive manufacturing; capillary effect; PETG

Nomenclature A cross-section area of capillary !" pressure of air bubble trapped in capillary #$% capillary force &" dynamic pressure of flow in capillary '()

viscosity force between flow and capillary wall

* Corresponding author. Tel.: +44 (0) 1509 227030. E-mail address: K.Baxevanakis@lboro.ac.uk

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.2025.06.023