IMPORTANCE OF STRAIN ANALYSIS IN TRIBO-MODELING IN DEEP DRAWING

Abstract

In deep drawing of parts of irregular geometry made of thin metal sheets, as for instance are the parts of car body, in certain zones of the part exist significant differences in stress-strain schemes. Also, significant are differences in the way of realization of the contact between the metal sheet and tool, namely in the contact macro geometry, values of pressure, speed and temperature, friction is useful in certain zones, and in others it is not, etc. In that sense several physical tribo-models were developed, elementary and complex ones, that are related to characteristic zones of the piece that is being drawn: sliding between the flat surfaces of the die and the holder, sliding over the draw bead, bending with tension over the die edge, two-way tension-stretching under the front of the drawing tool, and pure deep drawing in the zone of tangential compression on the flange. Results of tribological investigations can be divided into three groups, according to the nature of parameters that represent the measured variables in realization of corresponding modeling.