TY - JOUR

T1 - Strain rate-dependent failure modes of material extrusion-based additively manufactured PETG

T2 - A study on crack deflection and penetration

AU - Waly, Christoph

AU - Schulnig, Sandra

AU - Arbeiter, Florian

N1 - Publisher Copyright: © 2024 The Author(s)

PY - 2024/12/18

Y1 - 2024/12/18

N2 - The layer-by-layer nature of fused filament fabrication (FFF) introduces interfaces along the build direction (z-axis). A crack approaching an interface may deflect or penetrate subsequent layers, based on the relative strengths of the interface and the matrix. This study evaluates the applicability of the Cook & Gordan (C&G) model for predicting crack deflection or penetration in glycol-modified poly(ethylene terephthalate) (PETG) printed structures, considering different print orientations and layer heights. The loading rate was varied between 0.1 and 1000 mm/min to identify potential rate-dependent effects. Interface and matrix strengths were determined through tensile testing, and their ratio was used to assess the validity of the C&G criterion. The results, supported by fracture mechanical validation experiments, indicate that the C&G model can effectively predict crack paths in FFF-printed PETG structures, provided that the assumptions of linear elastic fracture mechanics are not significantly violated. Accurate predictions were unattainable at the lowest loading rate (0.1 mm/min). For loading rates ≥ 10 mm/min the criterion appears plausible, aligning with previous studies.

AB - The layer-by-layer nature of fused filament fabrication (FFF) introduces interfaces along the build direction (z-axis). A crack approaching an interface may deflect or penetrate subsequent layers, based on the relative strengths of the interface and the matrix. This study evaluates the applicability of the Cook & Gordan (C&G) model for predicting crack deflection or penetration in glycol-modified poly(ethylene terephthalate) (PETG) printed structures, considering different print orientations and layer heights. The loading rate was varied between 0.1 and 1000 mm/min to identify potential rate-dependent effects. Interface and matrix strengths were determined through tensile testing, and their ratio was used to assess the validity of the C&G criterion. The results, supported by fracture mechanical validation experiments, indicate that the C&G model can effectively predict crack paths in FFF-printed PETG structures, provided that the assumptions of linear elastic fracture mechanics are not significantly violated. Accurate predictions were unattainable at the lowest loading rate (0.1 mm/min). For loading rates ≥ 10 mm/min the criterion appears plausible, aligning with previous studies.

KW - Crack Deflection

KW - Crack Penetration

KW - FFF

KW - Fracture Testing

KW - Fused Filament Fabrication

KW - Strain Rate Dependency

KW - Tensile Testing

UR - http://www.scopus.com/inward/record.url?scp=85212860917&partnerID=8YFLogxK

U2 - 10.1016/j.tafmec.2024.104834

DO - 10.1016/j.tafmec.2024.104834

M3 - Article

AN - SCOPUS:85212860917

VL - 136.2025

JO - Theoretical and Applied Fracture Mechanics

JF - Theoretical and Applied Fracture Mechanics

SN - 0167-8442

IS - April

M1 - 104834

ER -