Analysis of shear band instabilities in sintered metals

For structural components made of sintered metals the porosity may be rathe r high, and this affects conditions for material failure. A simple model fo r analysis of shear band development in uniformly strained solids is used h ere to study the effect-of rather high initial porosities on the onset of a material instability. The elastic plastic behaviour of the material is rep resented by a material model, which combines the Gurson model, relevant to rather low porosities, with the FKM model, developed for high porosity powd er compacts. Predictions are shown for various levels of initial porosity a nd for various levels of initial material:imperfections, considering both p lane strain and axisymmetric conditions outside the shear band. Also a comp arison of localization predictions by the Gurson model, the FKM model and t he combined model is presented. (C) 1999 Elsevier Science Ltd. All rights r eserved.