Experimental validation of a differential variational inequality-based approach for handling friction and contact in vehicle/granular-terrain interaction

• A validation study was carried out in order to assess the DVI contact model for DEM.
• The novel DVI model is based on complementarity conditions for frictional contact.
• The model has been implemented in an open-source, dynamics engine called Chrono.
• A unique set of DEM parameters was used to match experimental data in three tests.
• This study concludes that the predictive attribute of the methodology is good.

The observation motivating this contribution was a perceived lack of expeditious deformable terrain models that can match in mobility analysis studies the level of fidelity delivered by today’s vehicle models. Typically, the deformable terrain-tire interaction has been modeled using Finite Element Method (FEM), which continues to require prohibitively long analysis times owing to the complexity of soil behavior. Recent attempts to model deformable terrain have resorted to the use of the Discrete Element Method (DEM) to capture the soil’s complex interaction with a wheeled vehicle. We assess herein a DEM approach that employs a complementarity condition to enforce non-penetration between colliding rigid bodies that make up the deformable terrain. To this end, we consider three standard terramechanics experiments: direct shear, pressure-sinkage, and single-wheel tests. We report on the validation of the complementarity form of contact dynamics with friction, assess the potential of the DEM-based exploration of fundamental phenomena in terramechanics, and identify numerical solution challenges associated with solving large-scale, quadratic optimization problems with conic constraints.