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In the forming of TB (Tailored Blank) side outer panel, splits frequently occur in the stretch flange areas. Most splits in these areas are categorized as two different types - one at the end of weldline in blank corner due to the local concentration of deformation on thinner or weaker material resulting from different material gauges or strengths and the other at the die corner due to the lack of draw-in of blank during stamping. Therefore, the proper design of blank shape, weldline placement and drawbead in the stretch flange area is crucial for the successful forming of TB side outer panel. In this paper, the design practice of TB stretch flange forming was investigated. The effects of the selected design parameters such a blank corner radius, weldline position and drawbead restraint forces were examined separately and the optimal TB stretch flange design was examined with respect to the several design parameters.

The dynamic behavior of an epicyclic gear train (EGT) with planet gears supported by journal bearing has been analyzed. The nonlinear stiffness of the gear teeth mesh was considered in the dynamic equations. Hydrodynamic bearing analysis on the fluid film between the planet gears and the shafts was executed to calculate the non-linear equivalent stiffness and damping coefficients. Interactive reactions between the gear dynamics and the bearing characteristics has been included. By this analysis, the gear tooth mesh forces at the sun/planet (S/P) and the planet/ring (P/R) gear meshes, the loci of the sun gear as well as planet and ring gear center, and bearing forces on the planet gear shaft have been calculated. Experiments have also been carried out to compare the calculated results using a simple star type planetary gear train. Calculated results have good correlation with experimental values.