PSI - Issue 38

Michaela Zeißig et al. / Procedia Structural Integrity 38 (2022) 60–69 Zeißig, Jablonski / Structural Integrity Procedia 00 (2021) 000–000

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specimens as it is possible to extend them to incorporate the main fatigue influencing parameters of AM specimens. As these may not be the same for all materials, for general usability, this versatility is an advantage. In order to make full use of the approaches, a broader experimental data base is required, as the sensitivity of the approaches towards variations of input data has shown. Experimental data base refers to fatigue data, especially with respect to building parameters, as these have a significant influence on the fatigue properties and needs to be determined across the different materials used in AM. Furthermore, once the necessary material and experimental data is available for the different materials, a fully transversely isotropic fatigue assessment should be carried out where reasonable in order to omit estimations based on the lowest directional properties. Moreover, data regarding residual stresses and residual stress sensitivities is necessary. A combination of this data allows calculations taking manufacturing direction and main load direction into account thus allowing optimal use of the geometric freedom of the AM process. As it seems unlikely to produce SLM specimens without any kind of defects, these should be included in the fatigue models as is done by the two approaches shown. In combination with a broad data basis for AM materials and with the use of FE calculations, both approaches are versatile tools for the fatigue assessment of SLM materials and seem especially useful in the context of defect tolerant concepts. Furthermore, a greater emphasis should be placed on the assessment of as-built specimens as the high surface roughness and residual stresses significantly influence the fatigue life. Moreover, the fatigue approaches should include a trade-off between different failure mechanisms. This applies in particular to the effect of defects and microstructure whose sizes might even be in the same order of magnitude as discussed for 316L by Zhang, Sun et al. (2017). Acknowledgements The authors gratefully acknowledge the financial support by the Deutsche Forschungsgemeinschaft (DFG - German Research Foundation) under contract no. 275999847. References Abaqus Welding Interface (AWI) 2017, Dassault Systems Simulia Corp., User Manual, 2018, AWI Version AWI_2017-5. Blinn, B., Klein, M., Beck, T., Hénaff, G., 2018. Determination of the anisotropic fatigue behaviour of additively manufactured structures with short-time procedure PhyBaL LIT. MATEC Web Conf. 165, 02006. Bomas, H., Mayr, P., Schleicher, M., 1997. Calculation method for the fatigue limit of parts of case hardened steels. Materials Science and Engineering, A 234, 393–396. Bräunig, J., Töppel, T., Müller, B., Burkhardt, M., Hipke, T., Drossel, W.-G., 2015. Advanced Material Studies for Additive Manufacturing in terms of Future Gear Application. Advances in Mechanical Engineering 2014, 741083. Crossland, B., 1956. Effect of large hydrostatic pressures on the torsional fatigue strength of an alloy steel. Proc. Int. Conf. on Fatigue of Metals. London: Inst. Mech. Eng., 138–149. Dassault Systemes Simulia Corp. (2016). Abaqus/CAE 2017. Edwards, P., Ramulu, M., 2014. Fatigue performance evaluation of selective laser melted Ti–6Al–4V. Materials Science and Engineering, A 598, 327–337. Forrest, P. G., 1962. Fatigue of Metals. Pergamon Press, Oxford. Gläßner, C., Blinn, B., Burkhart, M., Klein, M., Beck, T., Aurich, J.C., 2017. Comparison of 316L test specimens manufactured by Selective Laser Melting, Laser Deposition Welding and Continuous Casting, in “7. WGP-Jahreskongress“. In: Schmitt, R.H., Schuh, G., (Eds.), Apprimus, Aachen, pp. 45–52. Hatami, S., Ma, T., Vuoristo, T., Bertilsson, J., Lyckfeldt, O., 2020. Fatigue Strength of 316 L Stainless Steel Manufactured by Selective Laser Melting. Journal of Materials Engineering and Performance 29(5), 3183-3194. Hück, M., Thrainer, L., Schütz, W., 1983. Berechnung von Wöhlerlinien für Bauteile aus Stahl, Stahlguss und Grauguss — Synthetische Wöhlerlinien. In: Bericht ABF 11 (Verein deutscher Eisenhüttenleute). Stahleisen, Düsseldorf. Jablonski, F., 2001. Rechnerische Ermittlung von Dauerfestigkeitskennwerten an einsatzgehärteten Proben aus 16 MnCrS 5 unter Berücksichtigung von Mittel- und Eigenspannungen. PhD thesis, University of Bremen, Shaker, Aachen. Kahlin, M., Ansell, H., Moverare, J. J., 2017. Fatigue behaviour of notched additive manufactured Ti6Al4V with as-built surfaces. International Journal of Fatigue 101, 51-60. Koehler, H., Schumacher, J., Schuischel, K., Partes, K., Bomas, H., Jablonski, F., Vollertsen, F., Kienzler, R., 2012. An approach to calculate fatigue properties of laser cladded components. Production Engineering 6 (2), 137–148.