Simulation of Soil - Machine Interaction in Agricultural Engineering Simulationsansätze für die Boden- und Wechselwirkungssimulation in der Landtechnik Dipl.-Ing. (FH) M. Obermayr MSc, Dr.-Ing. Y. Öngün, Dr. K. Dreßler, Fraunhofer ITWM, Kaiserslautern; Abstract The simulation of granular media, in particular the simulation of soil is still under ongoing research. In classical soil mechanics, the focus of interest lies mainly on the stability of the material. Usually, there is no need to model large deformations or the separation of the material. For numerical simulations, the Finite Element Method (FEM) is well established in this field. In the design of agricultural machinery, construction equipment etc. engineers need to simulate the working process of the machinery, including the material handling like ploughing, excavation, mixing of granular material or its transport. Due to the complexity of the physical properties of soil and due to the variety of simulation tasks in this field, different numerical methods have to be used in order to capture the physical behavior of all possible tasks. In this study, two different problems for soil simulation and possible solutions to them are shown. The first one is the interaction between a flexible tire with deformable soil. The second problem aims to predict the forces acting on a blade that is moved through soil as it happens during ploughing or excavation. 1. Introduction The variety of simulation tasks related to soil interaction is large: Results of a numerical simulation can be used to predict damage on the harvest [1] or to predict reaction forces on machine parts during their operation, analyze the mixing of granular material and so forth. Not only the number of different tasks is large, but also the number of available numerical methods has increased over the last years. The nonlinear material properties and the large strains, including material separation, are the main difficulties that occur in soil simulation. The Discrete Element Method (DEM) [2] has become popular for this kind of tasks as it intrinsically allows for separation of material and can be easily extended to include effects like cohesion or bonding of particles. On the other hand, the local contact parameters have to