Mathematical modelling of isostatic pressing

This paper makes use of the considerable advances that have been made in the understanding of the mechanics of soil to provide a basis for the mathematical modelling of the isostatic pressing of ceramic batches. The mechanical properties of granular materials are reviewed initially from a non-mathematical point of view and this is followed by a brief mathematical treatment of uniform compaction under hydrostatic and shear stresses. A general method of simulating non-uniform compaction is then outlined. The paper closes with some examples of interest. These include the compaction of a powder around a rigid cylindrical mandrel and the compaction of a powder inside a square sectioned elastomeric bag. An important prediction is that the distortions commonly produced during isostatic pressing should be reduced by matching the bulk modulus of the elastomer to the 'effective bulk modulus' of the powder.