Numerical Simulation Of The Interaction Of Tractor Tyre With Soft Ground

The tyre is the part of the tractor in direct contact with the soft ground during the field operation.An in-depth study of the interaction between the tyre and the ground is of great significance for the structural optimisation and performance improvement of the tractor,and for solving the tractor passability problem.The test method to study the interaction between tyres and soft ground can only obtain macroscopic data such as the traction force of the tractor’s hitch and the amount of tyre sinkage;it cannot analyse the detailed data such as stress and strain during the interaction between tyres and ground;and the test method requires high test conditions and high test costs.Based on the above considerations,this paper relies on the national key research and development project sub-project "intelligent design of high-power tractor ’three’technology and tractor walking system intelligent design technology research",for the Dongfanghong LF-2204 tractor drive wheel,using The finite element simulation method is used to study the interaction between the tyre and the soft ground.The main work and conclusions of this paper are as follows.(1)Tractor tyre finite element modelling and verification.The actual tyre structure is reasonably simplified,on the basis of which the geometric model of the tyre is established;the Yeoh model is used to describe the mechanical properties of the tyre rubber material,and the parameters in the Yeoh model are determined through the uniaxial tensile test of the rubber material;the rubber-cord composite model is established through the setting of rebar cells;finally,the mesh is divided for the tyre model,and the finite element modelling of the tractor tyre is completed.Finally,the tyre model was meshed to complete the finite element modelling of the tractor tyre.The relationship between tyre deformation and tyre pressure and vertical load is determined through the tyre static pressure test;the tyre deformation and the distribution of stress-strain and displacement are analysed qualitatively through the static pressure simulation,and the static pressure simulation data of vertical load and deformation under different tyre pressure are obtained.Finally,comparing the load and deformation curves obtained from the hydrostatic simulation and test under various tyre pressure conditions,the validity of the tyre finite element model was verified.(2)Tractor tyre and soft ground interaction simulation analysis and test verification.Field traction tests of the tractor were carried out to obtain test data on the tractor’s hook traction and sinkage at 3.6km/h,5.4km/h and 7.2km/h.At the same time,a finite element model of the ground was established,and combined with the tyre model established above,a finite element model of the tyre contact with the soft ground was established;the rolling process of the tractor tyres under field traction was simulated and analysed,and by comparing the test results with the simulation results it can be seen that: within a driving distance of 20 m,the simulation results of the hitch traction force and the sinkage amount are basically the same as the test results;when the speed changes in the range of 3.6km/h-7.2km/h,the hook traction force increases with the increase of driving speed,and the maximum error between simulation and test is 6.9%;the sinkage volume increases with the increase of driving speed,and the maximum error between simulation and test is 5.5%.Through the simulation and test comparison,verify the validity of the tyre and soft ground contact model established in this paper and the reasonableness of the tyre rolling process simulation.(3)Tractor tyre traction characteristics of the simulation analysis.The influence of tyre structure(wheel diameter,wheel width,tread pattern)on the hook traction force and sinker volume is studied,the results show that: within a certain range,with the increase of tyre slip rate,the hook traction force and sinker volume increase;when the slip rate exceeds 30%,the increase of hook traction force and sinker volume tends to level off;with the increase of tyre diameter and width,the hook traction force and sinker volume of the tyre will increase,and changing The effect of changing wheel diameter on hook traction and sinkage is more pronounced;under the same slip conditions,tyres with a tread pattern have a greater effect on hook traction and sinkage than tyres without a tread pattern.The effect of tyre driving parameters(vertical load,rotational speed and tyre pressure)on hook traction and sinkage is studied.The results show that: with the increase of vertical load and rotational speed,hook traction and sinkage increase,and the effect of vertical load on hook traction and sinkage is more obvious.And with the increase of tyre pressure,the hook traction force and sinkage decreased.