In this paper, fatigue initiation of railway wheels is studied from a theoretical point of view using a computer analysis of the state of stress and strain. The drawback of computational simulations is that the validity of the results is completely relying on the adequacy of the theoretical models. However, the approach permits a fairly fast analysis of the influence of different parameters such as load level, contact geometry, defect position etc. Some conclusions of practical interest may be drawn from the above results: -The state of stress at the defect exhibits a complex evolution during a load cycle (i.e. a load passage); -Stress gradients at a defect are large, a fact which raises questions regarding fatigue design. lf stresses/strains at nodes (or integration points) in a FE-model are used in the fatigue analysis, the results may be overly conservative. There are proposals that stresses and strains should be averaged over a characteristic area, such as the grain size. However, due to the large gradients, the results will depend heavily on the area chosen; -The type of response at the defect depends on the combination of load magnitude and vertical position of the defect. This has to be taken into account when identifying admissible load magnitudes (or defect sizes); In contrast to the case of a 'defect-free material' the contact geometry seems, for moderate loads, to be of minor importance for the fatigue impact of a defect. Subsequent studies should broaden the scope to include parameters such as size and shape of defects. The results obtained from the present and the future studies will be introduced in a predictive fatigue design model for railway wheels.
Fatigue initiation in railway wheels - a numerical study of the influence of defects
Initiierung der Materialermüdung in Eisenbahnrädern - eine numerische Untersuchung des Einflusses von Defekten
2002
9 Seiten, 13 Bilder, 14 Quellen
Conference paper
English
Fatigue initiation in railway wheels - on the influence of defects
British Library Conference Proceedings | 2000
|Effects of imperfections on fatigue initiation in railway wheels
Online Contents | 2000
|Effects of imperfections on fatigue initiation in railway wheels
British Library Online Contents | 2000
|Effects of imperfections on fatigue initiation in railway wheels
SAGE Publications | 2000
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