PSI - Issue 42

686 Marouene Zouaoui et al. / Procedia Structural Integrity 42 (2022) 680–686 Author name / Structural Integrity Procedia 00 (2019) 000 – 000 7 compared to the solid specimen but especially to the huge weight reduction. The auxetic cells at 0° is by far the most performant ( = 3.45 ). The specimen is able to absorb a high amount of energy while reducing its weight by almost half. The mechanism of deformation of the auxetic cells allows a direct axial deformation in the notch direction that will cause a delay of the crack initiation and therefore hold back the fracture timing. 4. Conclusion A feasibility study via the energy to fracture assessment was performed using SENB specimens. The effect of introducing cells on the specimen surface was investigated by testing different cell forms manufactured by extrusion metallic 3D printing. The purpose was to test the influence of auxetic and honeycomb cells on the fracture behavior and damage initiation in the sample. The analysis leads to the following conclusions: • Auxetic cells change the fracture behavior and delay the crack initiation compared to classic specimens studied • Auxetic cells parallel to the notch direction most improves the fracture toughness compared to the other patterns studied • The failure of the SENB samples occurs by (i) the crack growth from the notch as well as (ii) the debonding of the interface between cells. • The reduction of weight is favorable to a more lightweight mechanical structure Future works should consider the potential effects of cells orientation and their density as design parameters in the DfAM approach. Besides, the local fracture behavior will be analyzed. This behavior can be highly influenced by the local geometry close to the notch tip. Specific modifications of the local geometry could be beneficial to improve fracture toughness. Acknowledgements The authors are grateful to the FabAdd Platform of EPF Troyes for manufacturing the samples, Troyes Champagne Métropole (TCM), and Aube Department Council (France) for their financial support. References Gardan, J., 2019. Smart materials in additive manufacturing: state of the art and trends. Virtual and Physical Prototyping 14, 1, 1–18. Wu, G., Langrana, N. A., Sadanji, R., Danforth, S., 2002. Solid freeform fabrication of metal components using fused deposition of metals. Materials & Design 23-1, 97–105. Markforged Metal 3D Printer: The Metal X 3D Printing System. Markforged. https://markforged.com/3d-printers/metal-x (accessed May 31, 2021). Bouaziz, M. A., Djouda, J. M., Kauffmann, J., Hild, F., 2020. Microscale mechanical characterization of 17-4PH stainless steel fabricated by Atomic Diffusion Additive Manufacturing (ADAM), Procedia Structural Integrity 28, 1039–1046. Henry, T. C., Morales, M. A., Cole, D. P., Shumeyko, C. M., Riddick, J. C., 2021. Mechanical behavior of 17-4 PH stainless steel processed by atomic diffusion additive manufacturing, Int J Adv Manufacturing Technology 114, 7–8, 2103–2114. Galati, M., Minetola, P., 2019. Analysis of Density, Roughness, and Accuracy of the Atomic Diffusion Additive Manufacturing (ADAM) Process for Metal Parts, Materials 12-24, 4122. Kolken H. M. A., Zadpoor, A. A., 2017. Auxetic mechanical metamaterials, RSC Adv. 7-9, 5111–5129. Meena, K., Singamneni, S., 2019. A new auxetic structure with significantly reduced stress concentration effects, Materials & Design 173, 107779. Beharic, A., Rodriguez Egui, R., Yang, L., 2018. Drop-weight impact characteristics of additively manufactured sandwich structures with different cellular designs, Materials & Design 145, 122–134. Eiger 3D Printing Software, Markforged. https://markforged.com/software (accessed May 31, 2021). Keiichiro, T., Hitoshi, I., 1992. Elastic-plastic fracture toughness test under mixed mode I-II loading, Engineering Fracture Mechanics, 41-4, 529– 540.