PSI - Issue 39

Mario Álvarez-Blanco et al. / Procedia Structural Integrity 39 (2022) 379–386 Author name / Structural Integrity Procedia 00 (2021) 000–000

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DIC technique has allowed a better visual analysis and understanding of the fracture, by showing the deformation of the grid joints before and after failure. From a microscope view, it can be observed that the grid pattern design and the trajectory followed by the nozzle are critical to the fracture mechanism of the tested specimens. The accumulation of material at the joints of the inner pattern when the nozzle travels twice through these points generates a reduction of the filament cross-section in each layer. These printing defects lead to local weakening of the structure in these areas where the crack nucleation is promoted. 4. Conclusions As a result of this preliminary research to analyse the fracture morphology of 3D-printed lattice-core PLA specimens, the following conclusions can be drawn: • Crack path analysis and DIC technique provide important information of manufacturing defects affecting failure in 3D printing components. • By means of uniaxial tensile tests and strain data acquisition, relevant information about the plasticity of PLA in the neck of the sample has been obtained. • Infill core density directly affects failure mechanism under three-point bending tests. • Crack paths are significantly influenced by FDM process parameters, such as the nozzle trajectory. • Alternative core designs will be studied to minimize printing defects in future researches. Acknowledgements The authors gratefully acknowledge the funding support received from the Spanish Ministerio de Ciencia e Innovación for funding the project PID2020-112628RA-I00 and the Comunidad Autónoma de Madrid through the project IND2020/IND-17413. References Ameri, B., Taheri-Behrooz, F., Aliha, M.R.M., 2021. Evaluation of the Geometrical Discontinuity Effect on Mixed-mode I/II Fracture Load of FDM 3D-printed Parts. Theoretical and Applied Fracture Mechanics, 113. Carlsson, L.A., Matteson, R.C., Aviles, F., Loup, D.C., 2005. Crack Path in Foam Cored DCB Sandwich Fracture Specimens. Composites Science and Technology, 65, 15-16. Gorelik, M., 2017. Additive Manufacturing in the Context of Structural Integrity. International Journal of Fatigue, 94, 168-177. Khosravani, M.R., Schürmann, J., Berto, F. and Reinicke, T., 2021. On the Post-Processing of 3D-Printed ABS Parts. Polymers, 13(10), 1559. Özen, A., Auhl, D., Völlmecke, C., Kiendl, J., Abali, B.E., 2021. Optimization of Manufacturing Parameters and Tensile Specimen Geometry for Fused Deposition Modeling (FDM) 3D-Printed PETG. Materials, 14(10), 2556. Redwood, B., Schöffer, F., Garret, B., 2017. The 3D Printing Handbook: Technologies, Design and Applications. 3D Hubs B.V.. Solav, D., Moerman, M.K., Jaeger, A.M., Genovese, K., Herr, H.M., 2018. MultiDIC: An Open-Source Toolbox for Multi-View 3D Digital Image Correlation. IEEE Access, 6, 30520-30535. UNE-EN ISO 178:2010. Plastics. Determination of flexural properties. AENOR, Sept. 2011. UNE-EN ISO 527-1:2012. Plastics. Determination of Tensile Properties. Part 1: General Principles. AENOR, Nov. 2021. UNE-EN ISO 527-2:2012. Plastics. Determination of Tensile Properties. Part 2: Test Conditions for Molding and Extrusion Plastics. AENOR, Nov. 2021. Wiberg, A., Persson, J. and Ölvander, J., 2019. Design for Additive Manufacturing–A Review of Available Design Methods and Software. Rapid Prototyping Journal.