Evaluation of methods for experimental and analytical determination of the contour area of the contact patch of a pneumatic tire with a support base

Subject of study. The results of experiments on the estimation of the error of methods of experi-mental and calculated determination of the contour area for the ecological assessment of a mobile energy device (MED) are presented. There was used the example of modern radial tires 360 / 70R24 of Bel-89 and 18.4R34 of F-11 agricultural tractor MTZ-1025.2. in modes of non-nominal loading at nominal load on tires and changes in tire pressure within the range recommended for field work. The purpose of the study. To assess the possibility of improving the computational method for determining the contour area of the contact patch of the tire tread of a pneumatic wheel based on the mathematical model of V.L. Biederman. Materials and methods. The assessment was carried out for four ways of determining the area of the tire contact patch: 1) directly measuring the area using a digital photograph of the tire contact patch in Kompas-3D V13 software with the de-termination of the scaling and method error using a square from 100x100 mm graph paper; 2) calcu-lation by the formula of the area of an ellipse, using the length and width of the tire contact patch, measured with a tape measure directly from the obtained print; 3) by calculation, determined from the digital photograph in Kompas-3D V13 software; 4) by calculation, determined by calculation using the parameters of the universal tire characteristic (UTC). Results and discussion. As a result of the experiments, it was found that for modern radial tractor tires, the static deformation of which does not exceed 18-22%, the method of theoretical determination of the contour area of the tire contact patch using the UTC parameters can be applied with sufficient (for engineering practice) accuracy. Full convergence of the calculated and experimental contour areas of the tire contact patch can be provided by the coefficient of their ratio. Conclusions. The carried out assessment of the possibility of using methods for calculating the conditional contour area of the tire showed that these methods can be well used for a comparative assessment of the technogenic mechanical impact of propellers on the soil.