Numerical modelling of the powder compaction of a cup

The porosity and stress distributions in an axisymmetric cup have been analysed numerically. The finite element programme is based on rate independent, finite strain plasticity theory, and two different porous material models have been implemented. The first material model is a combination of the Gurson model, relevant to rather low porosities, and the Fleck–Kuhn–McMeeking (FKM) model, developed for highly porous powder compacts.

The second material model accounts for the possibility of reduced inter-particle cohesion. Friction between tool and work-piece as well as the compaction method have both a significant influence on the porosity distribution in the compacted cup. The inter-particle cohesive strength plays only a minor role in the porosity distribution, but is more important in both the distribution and the level of the von Mises and the hydrostatic stresses.