Computer simulations help to predict the behaviour of vehicles and to optimize their operation, with less effort than running real experiments. This can be used in the development process of agricultural machines as well as in the field operation. There are considerable differences between the simulation of passenger or transport vehicles in comparison to the simulation of agricultural machines. For example, the lack of suspension systems (especially on the rear axle), the tyre performance, the necessity of enough traction on the field, the repercussions on soil compaction and the versatility for the on-road and off-road use.
The Hohenheim Tyre Model (HTM) was successfully developed and validated at the Hohenheim University, it simulates, on the basis of a detailed spoke approach, the special behavior of high volume agricultural tyres on firm, uneven roads. The model implements three types of parameters, which can be determined with two in-house tyre test stands. In Co-simulation with whole vehicle multi-body simulation models (MBS) the HTM is used by research institutions and agricultural machinery manufacturers for driving dynamics and driving comfort investigations. The next step in the development of the HTM is the implementation on soft soil, thus making it possible to simulate scenarios related to trafficability, traction, tyre combination and ballasting. It could also be used, in combination with other models and tools for the prediction of fuel consumption and the soil compaction research.
The aim of this project is to investigate the soft-soil-tyre interaction in the vertical and longitudinal directions and to adapt the HTM so that a soil model can be integrated. For this it is also necessary to develop a soil model or to adapt an existing model, which makes it possible to determine the stress state in the contact patch and its corresponding positions.
