Soft Soil Tire Model Development and Experimental Testing
VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG
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Accurate and efficient tire models for soft soil operations are needed for mobility simulations of wheeled vehicles operating in off-road conditions. The tire model is essential in a vehicle model the accuracy of the predicted tire forces and moments has a large impact on assessing the vehicle performance, reducing the number of stuck vehicles, avoiding rollovers, and developing advanced control strategies. While finite element method leads to the most detailed tire-soil interaction models, their complexity and extensive computational effort make them less than ideal for the applications envisioned, requiring hundreds of thousands of evaluations. Semi-analytical models such as the F-tire were developed for on-road applications. The semi-analytical soft-soil tire model developed in this study employs a similar construction as F-tire and adds an advanced tire-soil contact model. The tire is discretized in a user-defined number of lumped masses structured in three layers two for the sidewall, one for the tread and belt, connected by elastic and damping elements connected in various configurations. Simulation results for several case studies performed with the tire model developed in this study are presented. In this paper we also present the experimental work related to soil testing and tire instrumentation and testing, as needed to collect input data and to validate the new off-road tire model. The soil of interest is silty sand. Soil characterization, performed in collaboration with Schnabel Engineering, will be presented. A physical tire has been instrumented with sensors able to collect deflection information in real time. Such information, in addition to the information received from a string potentiometer, is critical in allowing the estimation of the true sinkage versus just measuring the tire rut. Experimental results obtained for tire deflection with the instrumented tire on a quarter-car test rig will also be presented.
- Soil Mechanics
- Surface Transportation and Equipment