Design And Experiment Of Tire-soil Interaction Research Platform

The study of the interaction between agricultural tires and soil has important theoretical and practical significance for improving the passability and maneuverability of agricultural vehicles on soft roads and reducing the compaction and damage of tires to soil.In this paper,the method of combining computer numerical simulation and soil tank test is used to study the tire-soil interaction,and to explore the effect of various factors on soil compaction and shear,as well as tire subsidence and lateral slip.Since the currently widely used numerical simulation methods such as finite element and discrete element cannot simultaneously accurately describe the deformation of pneumatic tires and the motion characteristics of soil particles such as splashing and collision,this study proposes a tire based on the coupling method of finite element and discrete element.-Soil interaction simulation model,which can make up for the shortcomings of traditional simulation methods and accurately simulate the dynamic characteristics of tires and soil.The reliability of the simulation model is verified by conducting soil tank test by self-developed tire-soil interaction test device.The main contents of this study are as follows:(1)A device for tire radial compression test was developed,and a static analysis was made on the center axis of the tire,which may affect the test results.Under the maximum pressure,its strength and stiffness met the test requirements.The device was used to press down the tire under different air pressures,and the radial compression of the tire and the contact area between the tire and the rigid plate were obtained under different tire pressures.(2)The tire finite element model is established,and the radial compression test is simulated using the model.The tire radial compression and the contact area between the tire and the rigid plate are used as indicators to continuously modify the elastic modulus of the tire carcass until the above indicators are used.The optimal value of the elastic modulus can be determined as it is the closest to the actual experimental value.Simulation under the optimal parameters can obtain the maximum error of the simulation and experiment of the tire radial compression and the contact area between the tire and the rigid plate,which are 9.09%respectively and 8.63%;the minimum errors are 0.35% and 0.1%.(3)Use the EDEM software to calibrate the soil used in the test and the contact parameters between the tire and the soil.The Edinburgh Elasto-Plastic Adhesion model was used as the contact model between soils.Taking soil accumulation angle as the response value,the contact plasticity ratio,soil-soil rolling friction coefficient and adhesion branch curve power which have the most significant effect on soil accumulation angle were obtained through PlackettBurman test,steepest climbing test and Box-Behnken test.The optimal combination of indices is 0.08,0.1,and 4.8.The remaining parameters are as follows: the soil-soil static friction coefficient is 0.45,the restitution coefficient is 0.5,the meso-contact surface energy is 4,and the tangential stiffness factor is 0.35.The coefficient of static friction between soil and rubber was determined to be 0.88 based on the principle of the slope sliding method.On this basis,a two-factor general rotation center combination simulation test was designed,the rubber-soil rolling friction coefficient and restitution coefficient were calibrated,and the optimal combination parameters were determined to be 0.18 and 0.55.Comparing the stacking angle obtained by the combined simulation with the test proves that the calibration parameters are credible and can be used for subsequent tire-soil interaction simulation analysis.(4)The tire-soil coupling model is established,and the coupled simulation analysis of the tire driving process under different working conditions is carried out.Based on the calibrated soil discrete element parameters,soil trough models with horizontal and different tilt angles were established;the soil compaction in the experimental soil trough was measured,and the process was simulated.The reliability of the established soil trough model is verified.A tire dynamics model for different loads,speeds,tire pressures,passing times,and rolling driving conditions was established,a coupled simulation was carried out with the soil groove model.(5)A tire-soil interaction test device was designed to measure the displacement and stress of the tire and soil in all directions under different working conditions.Compared with the simulation results,the error is less than 10%,which proves that the finite element method proposed in this paper is based on the finite element method.Reliability of tire-soil interaction models coupled with discrete element methods.According to the obtained results,the effects of load,speed,tire pressure and number of passes on soil compaction and tire subsidence were studied,and the significance of each factor was evaluated.In addition,the effect of tire roll angle on soil shear and tire lateral slip was studied.impact of shifting.The results show that the above factors have an effect on soil compaction and tire subsidence.Load,tire pressure,and number of passes are positively correlated,and speed is negatively correlated.The order of significant influence is: load,tire pressure,number of passes,and speed;Under working conditions,the roll angle is positively correlated with soil shear and tire slip.