Modeling the interaction of soil with a combined tool - a knife roller and a pair of disc plows

Tillage during reforestation of cut-down areas faces the problem of low efficiency of traditional methods caused by complexity of forest soils, high cost of field experiments and limited reproducibility of results. This hinders creation of optimal technologies ensuring survival of forest crops and improvement of soil structure. The study is aimed at solving this problem through development of a computational model of interaction of forest soil with a com-bined tool, including a knife roller and two disc ploughs, using the discrete element method (DEM). The model allows analyzing the combined effect of working bodies on the soil, which is important for improving the quality of cultivation and reducing energy costs. Materials and methods of the study include modeling of soil as a set of spherical particles with specified physical properties (mass, position, velocity, force). Interaction of particles is described by a contact model with a spring and damper, and the geometry of the tools is imported from OBJ files created in computer-aided design (CAD) systems. The software implementation is implemented in Delphi. The study was conducted in several stages: determining the contact parameters, calculating the interaction forces, assessing the soil deformation and opti-mizing the tool design based on 20 computer experiments with varying factors (roller depth from -5 to 5 cm, lateral shift of plows from -5 to 5 cm, plow attack angle from 15-30). The results showed that the optimal tool parameters are: roller depth from -2 to -1 cm, lateral shift of plows 4-5 cm, plow attack angle 22-24. With these values, the coeffi-cient of loosening completeness exceeds 60%, the coefficient of soil turnover is 24%, the coefficient of ground cover crushing is 56%, and the resistance force to movement does not exceed 4800 N. Theoretically, this confirms the ap-plicability of DEM for accurate modeling of complex soil systems. In practice, the parameters provide a decrease in energy costs by 15-20% compared to traditional tools, improving the conditions for reforestation. The key benefit of the study for readers is the provision of scientifically substantiated parameters for the design of combined tools, which contributes to increasing the efficiency of reforestation work. The issue of adapting the model to soils with a high root content remains unresolved, which requires further research taking into account additional factors such as moisture and density of organic residues.