Designing belt seedling feeding mechanisms for forest planting machines requires ensuring a reliable grasp without damaging the living tissues of the planting material. Traditional field-testing methods for optimizing this process are resource-intensive. The purpose of the research is to develop and apply the discrete element method (DEM) to create a detailed virtual model of the belt feed process, which allows for parametric analysis of the force effect. The comprehensive DEM model was developed in the research. It integrates three subsystems: the discrete structure of the rubber belt (Kelvin-Voigt elastic-viscous model), the multifarious model of the seedling, taking into account bending forces, and the precise geometry of the roller mechanism. The model is implemented in a specialized software complex. The main analyzed parameter was the force of transverse compression of the seedling by the belts (Fc). Verification confirmed the physical correctness of the model. The spatio-temporal distribution of force Fc with pronounced maxima (up to 13. 5 N) in the contact zones with the rollers has been established. The minimum value of the force (7. 5 N) guarantees reliable traction throughout the entire trajectory. Comparison of peak force with the threshold for damage to the tissues of coniferous seedlings (15-18 N) showed a strength margin of >20%. Parametric analysis revealed a statistically significant increase in the average force by 7. 8% with an increase in the belt speed from 0. 5 to 1. 0 m/s. The developed DEM model is an effective tool for virtual prototyping. It allows for multi-variant analysis and optimization of the structural and operating parameters of the belt mechanism, ensuring a balance between grabbing reliability and seedling biomechanical safety, which reduces the costs of experimental design work.
Drapalyuk et al. (Fri,) studied this question.