Theoretical analysis of the supporting cross-country ability of the wheeled propulsion of a forest machine when working on a slope

The study is theoretical in nature and is based on the analysis of the numerical solution of the equation of rutting on forest soil, taking into account the loss of bearing capacity. The analysis of the results of a computational experiment performed by varying the mechanical properties of the soil, the angle of slope and the weight of the wheel mover allowed us to obtain a comprehensive assessment of the cross-country ability of the wheel mover of a forest machine operating on a terrain with a slope, on rough terrain. For the first time, formulas based on the results of processing calculated data were obtained, intended for practical justification of the permissible parameters of the wheeled propulsion of a forest machine operating on a slope. The calculated data obtained prove the importance of taking into account the angle of the slope on which wheeled forestry machines operate, from the point of view of practical justification of the permissible load parameters of the wheeled propulsion. The simulation results showed that with an insignificant slope angle of 5o, in order to ensure the supporting cross-country ability of the wheel mover, the weight allowed on the horizontal support surface should be reduced by 20-25%, with an angle of 10o, the required reduction in the weight of the mover is 40-50%. On relatively steep slopes from 15° and above, a decrease of 65% or more from the value allowed for operation on a horizontal support surface is required. This makes it possible to recommend equipping wheeled forestry machines with self–propelled winches already at slope angles of 10 - 15o to ensure the supporting cross-country ability of the propellers. The estimation of the required power is possible based on the results of the calculation of the coefficient of resistance to movement. It was found that at relatively small slope angles, up to 5 °, the assessment of the depth of the track at a weight acceptable according to the criterion of support patency is higher than 0.20 m, recommended from the point of view of environmental friendliness of the propulsion. With the weight of the mover acceptable according to the criterion of passability on steeper slopes, the estimated track depth is significantly less than 0.20 m, however, the actual deformation and damage to the soil will be higher, which is due to the impact of the mover's ground hooks. Nevertheless, while ensuring the cross-country ability of vehicles through the use of self-propelled winches, it is possible to predict a "reserve" increase in the permissible weight of the propulsion. Taking into account the above circumstances, in the future it is advisable to conduct separate studies aimed at studying the environmental friendliness of wheeled propellers of forest machines operating on slopes.