Identification, verification and validation of soil constitutive material model parameters for soil-tire/tool interaction numerical simulations

Soil-tire/tool interaction numerical simulations are extensively used to design and optimize various agricultural and off-road machinery. The accuracy of these simulations is highly dependent on the soil constitutive material model and numerical methods used. In the current study, a systematic approach is proposed for the identification and validation of the soil constitutive material model parameters based on laboratory and in-situ testing results of sandy loam soil. Based on the triaxial and consolidation testing results at three moisture contents, MohrCoulomb, Drucker-Prager, and Cap plasticity material model parameters are identified. The identification process repeatability is verified through the numerical simulations of the triaxial test. The triaxial test simulation results are correlated with experimental data and the overall accuracy and ability of these material models to predict the peak soil strength and failure strain is assessed. Later, cone penetrometer test (CPT) simulations with different numerical methods (Coupled Eulerian Lagrangian-CEL and Smooth Particle Hydrodynamics-SPH) are performed to validate the material model parameters. Numerical simulation results suggest that the Cap plasticity material model can predict the peak soil strength and failure strain with reasonable accuracy at all moisture contents compared to other material models for triaxial test simulations. Further, the Cap plasticity material model with the SPH method correlated well with the experimental data of CPT. Hence, through this study, a systematic approach for material model parameter identification is developed and validated, and the capability of different numerical methods and soil constitutive material models in the context of soil-tire/tool interaction modeling is evaluated.