PSI - Issue 68

J.A. Ziman et al. / Procedia Structural Integrity 68 (2025) 1159–1165 J.A. Ziman et al. / Structural Integrity Procedia 00 (2025) 000–000

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4. Conclusion and outlook Within the scope of this research, an increase in fatigue lifetime and an associated shift in the first material response to higher stress amplitudes with increasing test frequency was observed. The temperature-correction of the electrical resistance could be used to separate influence of the frequency-related specimen heating and thus provided a reliable input variable for the lifetime prediction method StressLife. The calculated S-N-curves are characterised by a precise agreement compared to validation data. This successfully demonstrated that StressLife can also be used at higher testing frequencies and provides a reliable lifetime prediction method, even above test frequencies of 5 Hz. The relaxation in surface residual stresses differs for different test frequencies and is more pronounced at 80 Hz in earlier fatigue stages and could be successfully correlated with the cyclic deformation behaviour. As part of future research, additional investigations in terms of scanning electron microscopy and the change in dislocation density based on X-ray diffraction measurements over the various fatigue stages will be analysed and compared with the fatigue behaviour. In addition, more test frequencies are used to better calculate and eliminate the frequency effect. Acknowledgements The authors would like to thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for the funding and support of the research project (project no. 518776466, STA 1133/22-1 and WA 1672/120-1) and the financial support for the procurement of the resonance testing system (project no. 468976436, INST 252/21-1 FUGG). The authors would also like to thank the University of Applied Sciences Kaiserslautern for its financial support in procuring the test infrastructure. Thanks are due to Ms. Hanna Jost for her support during the experimental implementation. Finally, thanks go to Russenberger Prüfmaschinen AG and XRD Eigenmann GmbH for their technical support. References Basquin, O. H., 1910. The exponential law on endurance tests. ASTM Proc. , 10 , 625–630. Coffin, L. F., 1954. A study of the effects of cyclic thermal stresses on a ductile metal. Journal of Fluids Engineering, 76 (6), 931–949. https://doi.org/10.1115/1.4015020 Dengel, D., Harig, H., 1980. Estimation of the fatigue limit by progressively-increasing load tests. Fatigue & Fracture of Engineering Materials and Structures , 3 (2), 113–128. https://doi.org/10.1111/j.1460-2695.1980.tb01108.x Eigenmann, B., Macherauch, E., 1996. Röntgenographische Untersuchung von Spannungszuständen in Werkstoffen. Teil III. Mat.-wiss. u. Werkstofftech. , 27(9), 426-437. https://doi.org/10.1002/mawe.19960270907 Harriehausen, T., Schwarzenau, D., 2019. Moeller Grundlagen der Elektrotechnik . Springer Fachmedien Wiesbaden. https://doi.org/10.1007/978 3-658-27840-3 Jenkin, C. F., 1925. High-frequency fatigue tests. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character , 109 (749), 119–143. https://doi.org/10.1098/rspa.1925.0110 Manson, S. S., 1953. Behavior of materials under conditions of thermal stress, Lewis Flight Propulsion Laboratory : Cleveland, OH, USA Matthiessen, A., 1865. On the specific resistance of the metals in terms of the B. A. unit (1864) of electric resistance, together with some remarks on the so-called mercury unit. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science , 29 (197), 361–370. https://doi.org/10.1080/14786446508643887 Starke, P., 2019. StressLifetc – NDT-related assessment of the fatigue life of metallic materials. Materials Testing , 61 (4), 297–303. https://doi.org/10.3139/120.111319 Teng, Z.; Wu, H.; Boller, C.; Starke, P., 2020. A unified fatigue life calculation based on intrinsic thermal dissipation and microplasticity evolution. Int J Fatigue 2020 , 131 , 105370. https://doi.org/10.1016/j.ijfatigue.2019.105370 Weber, F., Koziol, J., & Starke, P., 2023. StressLife: A short-time approach for the determination of a trend S-N curve in and beyond the HCF regime for the steels 20MnMoNi5-5 and SAE 1045. Materials , 16 (11), 3914. https://doi.org/10.3390/ma16113914 Wu, H., Bill, T., Teng, Z. J., Pramanik, S., Hoyer, K.-P., Schaper, M., & Starke, P., 2020. Characterization of the fatigue behaviour for SAE 1045 steel without and with load-free sequences based on non-destructive, X-ray diffraction and transmission electron microscopic investigations. Materials Science and Engineering: A , 794 , 139597. https://doi.org/10.1016/j.msea.2020.139597 Wu, H., Ziman, J. A., Raghuraman, S. R., Nebel, J.-E., Weber, F., & Starke, P., 2023. Short-time fatigue life estimation for heat treated low carbon steels by applying electrical resistance and magnetic barkhausen noise. Materials , 16 (1). https://doi.org/10.3390/ma16010032