THE ALGORITHM OF EXPRESS ASSESSMENT OF IMPACT ON SOIL OF RUNNING SYSTEMS OF TRACTOR-TRANSPORT UNITS

A reliable assessment of the level of impact on the soil from the propulsors of mobile agricultural machinery is possible only with an accurate measurement of the contour area of the contact surface of the tire with the support base. This indicator underlies all standard methods for determining the maximum normal pressure, maximum stresses and other indicators in the “wheel-soil” system. A simplified algorithm for determining the area of the contact patch of tires, which can be used both when assessing the level of pressure on the soil of existing trailed agricultural vehicles and newly developed ones, was proposed by the authors. In the first case, it is enough to measure the dimensional parameters of the tire mounted on the trailer: diameter, profile width, the amount of deformation under the influence of axial vertical load. In the second case, it is enough to take this data from catalogs with the technical characteristics of tires from specific manufacturers. The mathematical model used to determine the crosssectional area of the cylinder by the plane of the supporting surface located from the edge of the wheel at a distance equal to the tire deflection is the basis of the algorithm. The proposed methodology was tested by comparing the calculation results with the results of full-scale tests of 22 samples of agricultural tires installed on various types of transport and tractor units: carts, trailers, transfer bins. As a result of the research, a fairly high value of the modeling efficiency criterion was obtained (0.989), indicating a high level of convergence between the predicted (calculated) and observed (measured) values of the contact areas of the studied tire samples. Ease of use, versatility and accuracy sufficient for engineering calculations make the proposed algorithm convenient for wide practical use.