Study on the drawbead restraining force in the stamping processes (in Polish) Badarne oporów kolnierza wywołanych dzialaniem progów ciłgowych w procesach tłoczenia blach

This paper deals with the drawbead restraining force in the stamping processes. Nowadays, finite element analysis of the stamping processes is carried out using an equivalent drawbead model, in which the actual drawbead is replaced by its projection onto the binder surface. The restraining force produced by the actual drawbead is assigned to the nodes in the regular mesh of the equivalent drawbead. The simulation results can correspond closely with those observed in physical object, when the drawbead restraining force is reflected effectively by the equivalent drawbead model. The drawbead restraining force was shown, both experimentally and analytically, to be a complex function of drawbead position, drawbead geometry and friction conditions. Experimental results, in the form of force-displacement curves, are compared to the results obtained both from the analytical and the numerical models. It was found that correlation between the models and experiment is not high and the significant differences in drawbead restraining force obtained by this method exist. Finally, the regression model of drawbead restraining force has been built. The model allows us to predict accurately the influence of variations in material, geometry of the drawbead and friction condition.