Crack penetration versus deflection in extrusion-based additive manufacturing – Impact of nozzle temperature and morphology

Christoph Waly, Sandra Petersmann, Florian Arbeiter

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

Two different modes of fracture propagation can occur when a crack encounters a weak interface in a fused filament fabricated (FFF) part: the crack either deflects into the interface, or penetrates the subsequent layers. The objective of this work is to verify the suitability of an energy- and a strength-based criterion for predicting which failure mode will occur in FFF printed parts. Four different materials, glycol-modified poly(ethylene terephthalate), polylactide acid and two different poly(methyl methacrylate) grades were examined. Fracture mechanical tests were performed on single edge-notched bending specimens for the energy-based approach and tensile tests performed on dumbbell specimens for the strength-based approach. Additionally, porosity measurements and thermal analysis were carried out to provide structural information. The energy-based approach proved unreliable for failure mode prediction. Potential problems include failure to meet the requirements of linear elastic fracture mechanics and issues with notch design. The strength-based approach, in contrast, correctly predicted the crack path for all tested materials and seems a promising candidate for failure mode prediction in FFF materials.
OriginalspracheEnglisch
Aufsatznummer104032
Seitenumfang13
FachzeitschriftTheoretical and Applied Fracture Mechanics
Jahrgang127.2023
AusgabenummerOctober
Frühes Online-Datum5 Aug. 2023
DOIs
PublikationsstatusVeröffentlicht - Okt. 2023

Bibliographische Notiz

Funding Information:
This research was partly carried out as part of the eFAM4Ind project (877409), which is funded by the Austrian Research Promotion Agency (FFG) and the Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology (BMK). Moreover, the authors acknowledge support from the Montanuniversitaet Leoben. Special thanks go to Franz Grassegger for his valuable support in sample preparation.

Publisher Copyright:
© 2023 The Author(s)

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