A discrete element approach for modelling the compression of crop stems

• Virtual crop stems were created in the DEMeter++ software.
• Realistic data-based contact models were developed for stem interactions.
• The effect of plastic deformation and damage was incorporated in the models.
• The models were successfully validated by comparing simulations and measurements.

The discrete element method (DEM) offers a powerful tool for simulating the interactions of large numbers of particles. Recently, DEM was used to simulate the interactions of tubular particles. While the existing linear elastic and Hertzian contact models can approximate the reversible compression for small deformations, they are inadequate for larger deformations. Here, the force–deformation behaviour is highly non-linear and plastic. In this study, data based contact models were developed for crop stems. These models combine realistic deformation behaviour with a minimal number of model parameters. Furthermore, the effect of plastic deformation and damage was incorporated in the model. The contact models were successfully used to validate, through comparison of simulations and measurements, individual stem and bulk compression. A good agreement was found between both. These validated DEM contact models for compression of crop stems allow to simulate the processing of large numbers of crop stems.