Discrete element modelling of bulk behaviour of wheat (Triticum aestivum L.) cv. ‘Pionier’ during compressive loading

In this study, the Discrete Element Method (DEM) was employed as a computational approach to analyse the bulk behaviour of wheat (Triticum aestivum L., cv. ‘Pionier’) under compressive loading. A laboratory compression apparatus was utilised as a basis for the acquisition of data from compression tests. To ensure accurate DEM predictions, the physical, mechanical, and interaction properties of wheat kernels were experimentally determined for two different moisture contents (12.4% and 25.4% w.b.). Five particle models were constructed to represent the geometric shape of the kernel, with the model composed of five sub-spheres identified as the most suitable, ensuring an optimal balance between computational complexity and simulation accuracy. The bulk compression results from DEM simulations were compared to experimental data, revealing a good agreement for volumetric strain, bulk density increase, and bulk compressibility within the specified range of applicability. Simulations provided valuable insights into temporal and spatial variations of forces and deformations acting on individual particles, thereby enhancing the understanding of bulk behaviour at different compression levels. The moisture content was found to significantly affect the particle compressive forces, deformation capabilities, and bulk compression characteristics. In conclusion, this study demonstrated the great potential of DEM in predicting the bulk behaviour of wheat under compression, providing valuable information for practical storage and handling processes.