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Welded tubes are hydroformed into hollow parts in the automotive industry, engineering equipment, household appliances, etc. However, in order to obtain sound hydroformed products, it is necessary to predict the rupture behaviour and analyze the effects of process parameters on this failure condition during tube hydroforming. The purpose of this research is to reveal the randomness of potential rupture positions on marketed SUS304 stainless steel welded tubes by statistical method under hydroforming conditions. Firstly, the welded tubes were experimentally hydroformed at two loading speeds and digital image correlation technique was applied to capture the rupture positions. Then, the rupture positions were summarised using statistical analyses. Finally, the reasons behind the randomness of the rupture positions of SUS304 stainless steel welded tubes were further analyzed. The results show that the rupture positions were located between the circumferential angles of 3° and 26° at low loading speed, and between 4° and 24° at high loading speed. Frequency distribution histograms of the rupture positions displayed a certain level of diversity of the tubes in different groups. [ABSTRACT FROM AUTHOR]

Two configurations of assembled camshafts characterised by isometric-trilateral and logarithmic spiral crosssectional profiles of the cam-bores are proposed and assembled via tube hydroforming (THF). After being assembled, the contact status between the hollow shafts and cam-bores on the centre cross-sections of the assembled camshafts were investigated. The maximum fit clearances and the effective contact lengths were then measured to evaluate the assemblability of the camshafts by THF. The results indicated that the two novel assembled camshafts with isometrictrilateral and logarithmic spiral contact profiles demonstrate good, but differing assemblability--the former exhibits superior assemblability to the latter and smaller cam-bores display better assemblability. The assemblability could be enhanced by increasing the assembly hydraulic pressure, but this is not efficient with smaller cam-bores. [ABSTRACT FROM AUTHOR]