PSI - Issue 4

Stefan Kolitsch et al. / Procedia Structural Integrity 4 (2017) 95–105 Stefan Kolitsch/ Structural Integrity Procedia 00 (2017) 000 – 000

105 11

For the calculation of the endurance limit the stress based design concept using the Smith diagram is shown for different loading conditions and surface qualities. The predicted endurable stresses correlate acceptably with the experimentally determined endurance limits. Using the stress based design the high strength materials have a higher endurance limit (estimated from the ultimate tensile strength). Using fracture mechanics approaches for damage tolerant design, the Kitagawa-Takahashi diagram is used, where the admissible stress range depends on the crack length. Again, the predicted curves correlate acceptably with the experiments. Finally, it has been shown how the endurance limit for components containing cracks of a given size can be plotted in the commonly used Smith diagram. In conclusion, if one uses damage tolerant design concepts accounting adequately for the residual stresses from the bending process, high strength steels are, due to their improved wear resistance, promising candidate materials for switch components.

Acknowledgements

Financial support by the Austrian Federal Government (in particular from Bundesministerium für Verkehr, Innovation und Technologie and Bundesministerium für Wirtschaft, Familie und Jugend) represented by Österreichische Forschungsförderungsgesellschaft mbH and the Styrian and the Tyrolean Provincial Government, represented by Steirische Wirtschaftsförderungsgesellschaft mbH and Standortagentur Tirol, within the framework of the COMET Funding Programme is gratefully acknowledged.

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