Determination of discrete element method (DEM) simulation parameters for polymeric waste particles

Plastic consumption is on the rise, particularly in Europe, where million tonnes are produced each year, with only 10% recovered. Optimizing the recycling processes in all its phases is vital. Understanding particle movement in some components of the plastic recycling plants can be addressed by the Discrete Element Method (DEM). The characterization of DEM materials is often performed through the study of the angle of repose (AoR). This study aims to advance DEM simulation of shredded polymeric waste, proposing a scaling and calibration procedure of the relevant simulation parameters. A total of six distinct types of polymeric particles, with different shape and size, have been characterized in this study, measuring their density, their shape estimators, their size distribution and their angle of repose. The AoR has been measured through a hollow cylinder lifting test. First, sensitivity analyses have been performed to establish a suitable range for the numerical parameters and to reduce the dimensionality of the problem. Then, the scaling and calibration procedure is described and tested on the six batches. The proposed procedure allows to predict very well the AoR, with an error below 1%, and the other geometrical variables of a heap, although it deteriorates in fully predicting its shape when the sphericity of the particles decreases.

Graphical Abstract