Discrete element model development of ZTA ceramic granular powder using micro computed tomography

摘要

Particle based simulations in 3D space using discrete element method provide valuable insight into the static and dynamic granular phenomena. Such phenomenon have to be considered during the production of ceramic components made up of dry pressed granulated ceramic powders. In the present work, 3D geometric parameters of zirconia toughened alumina (ZTA) granules in terms of their shape, size and spatial distribution are obtained using state of the art micro computed tomography (μCT). Computed tomography data provided an ample amount of information to obtain a 3D arrangement of particles in a defined space for discrete element method simulations. However, during simulations, the residual forces initiate spatial disturbance of the particles which lead to their rearrangement, despite the fact that the particle assembly while scanning was in a static equilibrium. Further appropriateμCT data processing steps along with statistical analyses of the polydisperse particle system are therefore proposed to dissolve the paradox. Possible pitfalls of model development are identified and corrected by geometrical and physical constraints. It is observed that the frequency of particle contacts can be used to characterize the stability of a particle system. Thereby, a coherent and consistent model in the form of a stable particle assembly for discrete element simulations is successfully developed.