Three-dimensional discrete element modelling of three point bending tests: The effect of surface energy on the tensile strength.

Understanding the dependence of the strength of agglomerates on material properties, interfacial properties and structure of the agglomerate is critical in many processes involving agglomerates. For example, for manufacturing of pharmaceutical tablets and pellets with dry granulation, understanding the relationship between the ribbon properties and the properties of granules is critical in controlling the granulation behaviour, and the ribbon properties (e.g. tensile strength and density distribution) is determined by the material properties of feed powders, interfacial properties between particles and the process condition, which determine the structure of ribbons. This study aims to investigate the effect of surface energy and porosity on the bending strength of pharmaceutical ribbons, for which three-dimensional discrete element modelling with a cohesive particle model based upon the JKR theory was performed. Simulations were carried out using specimens of various porosities and surface energies. The dependence of the bending strength on the surface energy and the ribbon porosity was examined. It was found that there is a strong correlation between the bending strength with the porosity and the surface energy. In particular, the bending strength is proportional to the surface energy and is an exponential function of the porosity. [ABSTRACT FROM AUTHOR]