PSI - Issue 75

Benjamin Causse et al. / Procedia Structural Integrity 75 (2025) 205–218 Author name / Structural Integrity Procedia (2025)

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We then showed that on a real signal (measured on a chairlift hoop) with a moderate variation in angle, pronounced biaxiality and a ratio R=0.23 (i.e.  m /  R =1.6) our charts, based on the Dang Van criterion, made it possible to evaluate very quickly the correct order of magnitude in multiaxial lifetime (noted N DVcharts ) simply by reading the chart, avoiding a complete Dang Van recalculation, which is very costly in terms of time and above all know how. Our charts (or abacuses) can therefore be used to quickly calculate Dang Van-type lifetimes, but for the moment our work is limited to typically proportional signals, and cannot be extended to complex non-proportional signals where only a full recalculation is appropriate (Dang Van or FKM or others). For the future, this work should generalise this method to different details categories (  c ) and different stress range = R values (by proposing a charts catalogue). On the other hand, and more generally, we can see that multiaxiality in chairlift hoops is not a new physical phenomenon. Since no remarkable pathology due to fatigue has been observed on these cableways safety components in the last 20 years, we can consider that the Eurocode usually applied with a safety coefficient  F =1.35 is safe and therefore covered multi-axiality. Subsequently, if we are interested in the multi-axiality of signals in cableways, it will be logical to try to adapt the safety coefficient in fatigue, in order to have a constant overall safety. Indeed, for future standardisation work, the cableway sector should find the right balance between not being too artificially conservative and still taking into account the analysis of multi-axial fatigue, which is an undeniable physical reality. Acknowledgements Many thanks to Stephane Contardo (STRMTG, head of the mechanical group, deputy director of the Notified Body 1267) for his support, as well as to Lucie Roux (deputy director of STRMTG and director of the NB 1267) for the fruitful discussions and English corrections. References Agard B., Giraud L., Fauvin F., Roux J.-C., Monnet P., Feulvarch E., 2022. Fast computation of critical planes for fatigue life analysis of metals, Vol. 350, p. 495-506. Aygül M., 2012. Fatigue Analysis of Welded Structures Using the Finite Element Method Department of Civil and Environmental Engineering. Ph. D. Thesis. Division of Structural Engineering, Department of Civil and Environmental Engineering, Division of Structural Engineering, Steel and Timber Structures, Chalmers University of Technology Bortolamedi, T., 2024. Rapporto di Prova / Test report LATIF n°23LA00069 and LEITNER ref. TR_D10644813EN_00 Site Measurement CD6 Leppleskofel – by LATIF for LEITNER (internal report), 52p. 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