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FROM:
Hiroki Yamashita (1), Paramsothy Jayakumar (2), Mustafa Alsaleh (3), and Hiroyuki Sugiyama (1)
(1) Department of Mechanical and Industrial Engineering, University of Iowa, Iowa City, IA 52242, USA
(2) U.S. Army Tank Automotive Research Development and Engineering Center, Warren, MI 48397-5000, USA
(3) Caterpillar Inc., Product Development & Global Technology, Mossville, Illinois, USA
“Physics-based deformable tire-soil interaction model for off-road mobility simulation and experimental validation”, Journal of Computational and Nonlinear Dynamics, Vol. 13, September 2017
ABSTRACT: A high-fidelity physics-based deformable tire-soil interaction model that can be fully integrated into multibody dynamics computer algorithms is developed for use in off-road mobility simulation. To this end, the finite-element (FE) tire simulation capability based on the flexible multibody dynamics approach, which allows for modeling the coupling of the structural tire dynamics and transient tire friction under hard braking and concerning maneuvers, is further extended to off-road mobility simulations. A locking-free nine-node brick element is developed by introducing an additional center node to the standard 8-node brick element, which defines the second derivative of the global position vector at this node, to alleviate the element lockings without special techniques such as the enhanced assumed strain approach. This allows for a straightforward implementation of the multiplicative finite strain plasticity theory along with the capped Drucker-Prager failure criterion to model the large plastic soil deformation exhibited as sinkage on deformable terrains. The tire-soil interaction model is fully integrated into the monolithic multibody dynamics computer algorithm to ensure the accuracy and numerical stability under transient vehicle maneuvers. In order to identify soil parameters including cohesion and friction angle, the triaxial soil test is carried out, and the soil model developed is validated against the test data. Use of the high-fidelity physics-based tire-soil simulation model in off-road mobility simulations, however, leads to a very large computational model to consider a wide range of terrains. Thus, the computational cost dramatically increases as the size of the soil model increases. To address this issue, the moving soil patch technique is applied such that the soil behavior only in the vicinity of the rolling tire is solved to reduce the model dimensionality associated with the finite-element soil model. It is shown that use of this approach leads to a significant reduction in computational time while ensuring the accuracy. Finally, the proposed off-road tire-soil simulation capability is validated against test data obtained from a soil bin mobility test facility, including the effect of wheel loads and tire inflation pressures on the longitudinal/cornering tire forces and the rolling resistance.
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