Basic studies of stalk structures with the Discrete Element Method for modeling agricultural processes

• Applicant: Professor Dr. Ludger Frerichs
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 256573739

Utilization of the Discrete Element Method (DEM) experiences an increasing spread in the simulation of processes in agricultural machinery. The suitability of DEM-Simulation also for stalk related processes can be taken for granted and there is a high potential expected for use in future machine and process development. But, the analyses of recent research work shows that the DEM-Simulation of stalk related processes has not been researched sufficiently. The simulation is not applicable satisfyingly, because the required kind and grade of complexity of the stalk models depending on the specific processes is unknown. So a standardized and systematic approach for process specific modeling of stalks does not exist. Furthermore the parameterization of the model has to be carried out by iterative procedures instead of using mechanical descriptions of the models for direct parameterization. The first key objective of this project therefore is to investigate basic process specific stalk models for DEM simulation, based on different basic stalk structures. These models shall be adapted to the respective requirements of the relevant processes (e.g. for conveying, cutting and compaction processes) and it shall be known how model modifications (e.g. grade of complexity) will affect the quality of the simulation results. In addition to this, at the end of the project a method will exist that describes for which stalk related process which model and which grade of complexity should be used.The second key objective of this project is a method for direct model specific parameterization of the bonds and particles. This method shall enable the parameterization of the model bonds and the particles properties in the DEM simulation without iteration steps after carrying out defined experiments to determine material parameters. Furthermore, measures shall be identified to reduce the model complexity in order to reduce the modeling and parameterization effort and especially to shorten the computation time. The models and methods will be validated by representative experimental tests. The central goal of this project is to provide a scientific basis for a simulation tool based on DEM to model stalk related processes. This shall lead to the knowledge which model structure has to be chosen depending on the specific process. In addition, there shall be findings for direct parameterization of model bonds and particle properties.

• DFG Programme: Research Grants