PSI - Issue 77

Miloslav Kepka et al. / Procedia Structural Integrity 77 (2026) 272–278

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Fig. 7. Follow-up research: calibration of fatigue damage accumulation hypotheses based on laboratory fatigue tests.

6. Conclusions Based on operational measurements in Pilsen and Bratislava, carried out on three SKODA trolleybuses, an analysis of the measured signals was performed using the rainflow method. Histograms of cumulative cycle frequencies were created for selected strain gauges located on welded joints of the bodywork profiles of the measured vehicles. This analysis showed that the stress spectra shape parameter ν is around the value of 1. This value was subsequently used to design the loading block and to calibrate the hypotheses of cumulative fatigue damage based on tests under variable loading. Acknowledgements The contribution has been prepared with the institutional financial support of the Ministry of Education, Youth and Sport of the Czech Republic. References Kepka, M., Kepka Jr., M., 2022. Forced Vibration of Bus Bodyworks and Estimates of Their Fatigue Damage. Recent Trends in Wave Mechanics and Vibrations, Proceedings of WMVC 2022, Mechanisms and Machine Science, Volume 125, pp. 241-248, Springer. Berger, C., Eulitz, K.-G.,Heuler, P., Kotte, K.-L., Naundorf, H., Schuetz, W., Sonsino, C.M., Wimmer, A., Zenner, H. 2002. Betriebsfestigkeit in Germany - an overview. International Journal of Fatigue 24, 603–625. Heuler, P., Klätschke, H., 2005. Generation and use of standardised load spectra and load–time histories. International Journal of Fatigue 27, 974– 990. Sonsino, C.M., 2007. Fatigue testing under variable amplitude loading. International Journal of Fatigue 29, 1080–1089.