Uticaj promenljivih tribo-uslova na položaj krive granične deformabilnosti tankih limova pri nemonotonom deformisanju

Abstract

The paper contains the experimental results of investigations of the tribo conditions influence on the position of the limiting deformability curve (LDC) in non-monotonous straining and a proposition of simple empirical-analytical way for definition of the LDC position with respect to contact conditions. Experiments includes two two-phase non-monontonous procedures. The first one (denoted as the schematic 2) in the first phase contains the uniaxial tension of the thin sheet stripes of the 200 mm width, while the second one (denoted as the schematic 4) the biaxial stretching realized by special stretching tool. In the second procedure is the LDC determination by stretching the series of samples with the variable width by the semispherical stretching tool. The influence of the tribo conditions was investigated by application of the extremal contact conditions. On one side those are dry contact surfaces degrease by acethone, and on the other side surfaces lubricated with oil and polyethylene foil.