A THREE-DIMENSIONAL FINITE ELEMENT MODEL FOR POWDER COMPACTION—TIME-DEPENDENT FORMULATION AND VALIDATION

Many industrial powders have been documented to have time-dependent compression response. However, in the literature very few time-dependent formulations are reported for three-dimensional analysis of powder compaction. In the paper, a time-dependent constitutive model, based on the theory proposed by Adachi and Oka, was used in a three-dimensional finite element formulation suitable for PC or desktop environments. The finite element model (FEM) predicts both the stress and density distributions in the powder mass during compression, i.e., from no load to the maximum compression load. A user-friendly interactive GUI (graphical user interface) was developed for the 3-D FEM, making it easy to use. To validate the FEM, microcrystalline cellulose was compressed to form cylindrical pellets using a press. The pellet was used to obtain spatial density distribution using the sectioning method. Then, the measured density distribution was compared with the Adachi and Oka model-based FEM calculated values. The density distributions were predicted within the 95% confidence interval of measured values. In addition, the overall error between the measured and predicted density values throughout the pressed pellet was less than 10%