This paper reports on the application of the Ultrasonic Impact Treatment on spokes of cast aluminium (AISiUMg) wheel spiders and its influence on spectrum loading. After preliminary investigations with specimens removed from the spokes for the adjustment of the treatment parameters, fatigue tests, measurement of residual stresses and metallographic analyses of untreated and treated spokes were performed. The mechanical impacts of the UIT effected a significant change of the microstructure, porosity and hardness. The application of the Ultrasonic Impact Treatment introduced plastic deformations and consequently compressive residual stresses at the surface. The fatigue strength increased significantly compared to the untreated spokes under constant and variable amplitude bending loading. The UlT-technology promises a high potential for improving of the structural durability and safety and the saving of material in the production of cast aluminium wheels. The investigations carried out reveal that under both constant and variable amplitude loading a significant performance increase was obtained. The fatigue strength increase of 21 to 26% does not yet seem to be the possible optimum due to the observed microcracks on the surface of the treated spokes However, the adjustment to more suitable parameters may lead to a further improvement. In this context it should also be mentioned that the UIT treatment of the spokes was performed manually Under industrial production conditions this would be carried out automatically and assure a controlled constant treatment quality. The increase of fatigue strength by UIT can also be used for a reduction of the cross sections of the spokes, if the fatigue life of the untreated component is sufficient and therefore maintained So, this treatment technology is able to realize lightweight design.
Fatigue strength under constant and variable amplitude loading of spokes of cast aluminium wheels after ultrasonic impact treatment (uit)
Ermüdungsfestigkeit bei konstanten und variablen Belastungsamplituden von Speichen in Aluminiumrädern nach einer Behandlung mit Ultraschallstößen
2009
8 Seiten, 11 Bilder, 1 Tabelle, 8 Quellen
Aufsatz (Konferenz)
Englisch
Tension of spokes in bicycle wheels
Engineering Index Backfile | 1897
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Tema Archiv | 2009
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