MODELING PRESSURE PATTERNS AND FAILURE OF CERAMIC CAKE DURING DRYING WITHIN PLASTER MOLD

Hydraulic pressure created by mould's suction within a ceramic cake fo rmed out of slipwater has been simulated over its length and time on t he analogy of a modified thermal Bow theory by diffusion-convection eq uation. The simulation results show that the pressure flow through the particulate medium of the cake, which also moves could lead to pressu re accumulation with time in the layers close to the mould-cake interf ace and consequently develop internal stresses of tensile nature in th e region. The results further indicate that the particulate cohesion o f the cake would be disrupted at 0.1 cm position at 7.1 minutes as the resultant stress could exceed the green item's tensile strength. (C) 1997 Elsevier Science Limited and Techna S.r.l.