Development, implementation and experimental validation of a novel hysteresis model for use in discrete element modelling of biomass materials

This research addresses the knowledge gaps present in the biomass industry, specifically the handleability and modelling of materials that undergo confined uniaxial consolidation. Although the discrete element method (DEM) has been widely used in the resources industry for years to model bulk material flow and handling systems, the applicability of DEM with the currently available contact models is questionable when applied to some of the material samples used throughout this research. The research consisted of experiments that were performed to examine the stress and strain relationship of the material samples. This experimentation was performed at two different scales (the small scale investigated consolidation pressures up to approximately 18 kPa and the large scale used pressures up to 100 kPa), then some of the current contact models were utilised to attempt to replicate the stress and strain behaviour of the samples in simulations. Drawbacks were found with the current models, evident by large errors between measured and simulated bulk responses, so a new model was developed. This model was verified against experimental data obtained from an automated loading and unloading tester. Addressed at the end of the thesis, there are recommendations given for direction of future work for the continual improvement of the experimental testing procedure and the simulation model.