PSI - Issue 42

Liviu Marsavina et al. / Procedia Structural Integrity 42 (2022) 1259–1265 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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(a) PLA material. (b) PETG material. Fig. 6. The nominal strength data for the two considered materials together with the asymptotic approximation given by eq. (1).

5. Conclusions The size effect of 3D printed PLA and PETG materials was experimentally investigated using SCB specimens obtained via FDM. Dimensional analysis based on the asymptotic matching shows that, for structures that are geometrically similar, the SCB specimens having the same shape, the nominal stress at failure varies with the structure size as  N  1/ (1+R/R 0 ) 0.5 . It could be observed that for larger structures the Linear Elastic Fracture Mechanics governs, which should be taken into account when large structures are designed and additive manufactured. The size effect law allow the determination of the energy release rate and the effective size of the fracture process zone of polymeric materials, by measuring the maximum loads of geometrically similar notched or cracked specimens of different sizes. Acknowledgements The project leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program (H2020-WIDESPREAD-2018, SIRAMM) under grant agreement No. 857124 and was supported by a grant of the Ministry of Education and Research, CNCS/CCCDI - UEFISCDI, project number PN-III-P3-3.6 H2020-2020-0079. References Ahmed, A.A., Susmel. L., 2019. Static assessment of plain/notched polylactide (PLA) 3D ‐ printed with different infill levels: Equivalent homogenised material concept and Theory of Critical Distances, Fatigue & Fracture of Engineering Materials and Structures 42(4): 883-904. Arbeiter, F., Spoerk, M., Wiener. J., Gosch, A., Pinter, G., 2018. Fracture mechanical characterization and lifetime estimation of near homogeneous components produced by fused filament fabrication. Polymer Testing 66, 105-113. Ayatollahi, M.R., Nabavi-Kivi, A., Bahrami, B., Yahya, M.Y., Khosravani, M.R., 2020. The influence of in-plane raster angle on tensile and fracture strengths of 3D-printed PLA specimens. Engineering Fracture Mechanics 237, 107225. Bahrami, B., Ayatollahi, M.R., Sedighi, I., 2020. The effect of in-plane layer orientation on mixed-mode I-II fracture behavior of 3D-printed poly carbonate specimens. Enginering Fracture Mechanics 231, 107018. Bažant , Z.P., Scaling of Structural Strength, Hermes-Penton, London, 2002. Bažant , Z.P., 1984. Size effect in blunt fracture: Concrete, rock, metal, Journal of Engineering Mechanics 110, 518–535. Ahmed, A.A., Susmel, L., 2018. A material length scale – based methodology to assess static strength of notched additively manufactured polylactide (PLA), Fatigue & Fracture of Engineering Materials and Structures 41(10), 2071-2098.