The soil moisture content (SMC) of moist clay directly affects the traction performance of off-road tire. This study set up a high-fidelity interaction model between off-road tire and moist clay with various moisture content, developed by coupling the finite element method (FEM) and smoothed particle hydrodynamics (SPH) algorithm. The interaction behavior between pneumatic tire and moist clay is studied. Firstly, a finite element model of tire which can characterize the complex structure and nonlinear mechanical properties is established. The Drucker-Prager (D-P) constitutive model parameters of clay with various moisture levels are calibrated by soil mechanical test. The moist clay with various moisture content is modeled through the SPH algorithm. The hybrid FEM-SPH interaction model is used to define the tire-moist clay interaction. Moreover, a traction performance test device suitable for tire-moist clay is developed to verify the accuracy of the interaction model. The influence of soil moisture content and tire operating conditions include vertical load and inflation pressure on the longitudinal traction coefficient, rolling resistance coefficient and instantaneous sinkage of tire center are quantitatively analyzed. The purpose of this study is to provide accurate tire force information under moist clay for unmanned ground vehicle (UGV), which can improve the problem of wheel instantaneous sinkage of tire center and slip under moist clay, and effectively reduce the yaw phenomenon in the path tracking process.

Modeling and performance prediction of tires on wet, plastic, cohesive soils is challenging. In wet soils, the undrained shear strength reduces as water content increases. This work aims to model highly deformable saturated clay (plastic state) to predict the short-term effect on the soil due to a single pneumatic tire pass. The external loads on the soil (total stresses) can be carried by the soil skeleton (effective stress) and/or water (pore water pressure). Fundamentally, effective stresses determine soil failure. Hence, material models can be defined using two frameworks: total and effective stress. In total stress analysis, commonly found in literature, soil and water are modeled as one medium to address rapid loading. In effective stress analysis, pore pressure evolution can be tracked through hydromechanical formulations with different drainage conditions (dry and fully saturated soils). Further, different numerical techniques (FEM, ALE, and SPH) are compared. The effective stress model captures an accumulation of excess pore water pressure after one tire pass resulting from soil non-linear behavior, which may potentially affect the tire performance of later passes. In addition, the FEM model fails at higher normal loads and slip ratios due to excessive deformation; ALE and SPH give more stable solutions for large deformations.1 (c) 2024 ISTVS. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.