Model for Compaction of Ceramic Powders

The use of the Coulomb yield criterion to describe the compaction of granular material is proposed. Its use is demonstrated by the numerical solu tion of the stress and displacement equations de scribing the axisymmetric pressing of a cylindrical compact. The model is applied to the pressing of uranium dioxide pellets; to do so, the shear strength of the pellets is measured as a function of normal stress. These measurements showed an increase of shear strength with normal load and permitted assignment of values of cohesion and angle of internal friction to be used in the Coulomb failure condition. The computed re sults of die wall friction, normal force at the die wall, and stress distribution in the compact are compared with measured results.