The Research On Simulation Analysis And Experimental Evaluation For Off-road Tires Driving Performance On Sand Terrain

Off-road tires are components that directly interact with sand terrain.The interaction between tires and sand greatly affects the passing ability,dynamics,ride comfort,and even handling stability and driving safety of off-road vehicles.Therefore,a systematic study of the interaction mechanism and mode of action between tire and terrain can provide effective technical guidance for the design,development and optimization of modern off-road vehicles.First,an indoor soil bin test platform is developed,and an off-road tire is used as a research object to systematically test its driving behavior on gravel and sand terrains.Based on the verification of the single-wheel soil bin consistency test,the driving performance parameters of off-road tires under different conditions such as slip rates,wheel loads,tread patterns,and soil types are obtained.The damage mechanism of gravel terrain below off-road tires under different working conditions is analyzed as well.The experimental research not only obtains the interaction relationship between off-road tires and different soil terrains under different operating conditions,but also provides an evaluation evidence for the subsequent numerical simulation method to study the effectiveness of tire-terrain interaction.Second,to improve the accuracy of the DEM-FEM simulation analysis of the off-road tire-gravel terrain interaction,a macro correction method is used to obtain the DEM-FEM model parameter.The DEM-FEM coupling method is used to establish and simulate the gravel triaxial test.After that,the mesoscopic parameters of the coupling model are iteratively adjusted to match the macro response(specimen stress-strain relationship and deformation)measured by the triaxial shear test to obtain the mesoscopic parameters of tire-gravel interaction.Then,based on the finite element open-source program DYNA3 D,a special analysis software DYNA3D-OVS for the study of sand-tire interaction is developed.The driving behavior of the tire-gravel terrain is simulated by the calibrated DEM-FEM model parameters and the software,and compared with the corresponding soil bin test results,which verifies the validity of the tire-gravel DEM-FEM coupling model parameters determined by the macroscopic calibration method and the numerical simulation method.Finally,the driving performance of off-road tires on sand terrain is simulated.In this paper,the rolling resistance model is introduced simultaneously with coarse-grainingtechnique to perform the equivalent treatment of irregular particles on sand terrain.A method of parameter calibration for the DEM-FEM coupling model of tire-sand based on design of experiments(Do E)is proposed.According to the calibration method and process,a single-factor numerical calibration test is performed in a specific order,and the unique and complete DEM-FEM model mesoscopic parameter set is determined when the off-road tire interacts with the sand terrain.The parameter set is then applied to the simulation model of the off-road tire-sand terrain interaction mechanism investigation.The simulation results are in good agreement with the corresponding soil bin test results,which verifies the correctness of the discrete element equivalent method and parameters calibration.This conclusion demonstrates that the discrete element model of sand terrain with proper scale can effectively evaluate the driving performance of off-road tires on sand terrain if the sand terrain is equivalent by using the discrete element with the appropriate particle size,and after the parameters of the DEM-FEM model have been calibrated through relevant tests.