Numerical approach using DEM to predict the failure mechanical response of porous brittle cylindrical tablets with a hole

Abstract

This paper deals with the development of a Discrete Element Method (DEM) based approach to reproduce the diametral compression test applied to dense porous cylindrical tablets with a hole. Stress Concentration Factor (SCF), which is the ratio of highest stress to the reference one obtained without hole, is assessed as function of hole size using a new halo definition for stress prediction. Results exhibit that the SCF is continuously increasing depending on the hole size, which agrees with experimental observations but differ somewhat from Finite Element Method (FEM) and theoretical predictions for which SCF is constant for small holes. Finally, the failure mechanical response of brittle cylindrical tablets with a hole is discussed. Two distinct behaviours are noticeable according to hole size. Thus, samples characterised by a ratio lower than 0.1 exhibit a brittle behaviour, while those characterised by a ratio higher than 0.1 display a quasi-brittle one.