Plastic behaviour of perforated sheets with slot-type holes under biaxial stress state

A yield criterion of sheets with slot-type holes under biaxial loading has been proposed in terms of apparent stresses. The yield criterion was confirmed by finite-element analysis results. In order to analyse stretching of a perforated sheet for slot-type shadow mask by finite-element method, a yield function which can incorporate the apparent yield stress and the apparent plastic contraction ratio has been obtained. The agreement between the measured and calculated results of stretch forming of the perforated sheet was satisfactory.