Features of the interaction of potato tubers with the working parts of potato harvesters

BACKGROUND: For the successful separation of potato tubers from the soil, it is necessary to consider the interaction of these tubers with the working bodies of potato harvesters. It is important to determine the forces acting on the tuber in the bed, as well as the parameters that may contribute to the damage of the tubers during mechanized harvesting. It is necessary to identify the damage criteria and to optimize work processes for reducing the loss of tubers due to insufficient separation of soil mass and other factors. AIM: Calculation of the tuber stress caused by the influence of the working parts and theoretical determination of the contact pressure acting on the tuber from the soil considering the condition of damageability of potato tubers. METHODS: The finite element method (FEM), which allows performing a detailed analysis of stress distribution at contacts between the tubers and working bodies, is used. RESULTS: The possibilities of applying the Hertz contact problem to the calculation of permissible parameters of load on a tuber were theoretically studied and the values of the permissible contact pressure were determined: qк = 0.034 MPa for a metal working body, qк = 0.15 MPa for an elastic one. At the same time, damage to potato tubers equipped caused by an elastic working body is significantly reduced. CONCLUSION: Contact loads that occur in tubers during interaction with metal working parts exceed the permissible stresses on the tuber, which causes damage to the tubers. To eliminate this drawback, the surface of metal working parts should be made elastic.