Damping Characterization Using Hysteresis on Static Nonrolling and Dynamic Rolling Behavior of Farm Tires4
This paper presents the characterization of damping behavior as characterized by hysteresis for farm equipment tires and time domain numerical simulation of off-road tire rolling using finite element techniques. The hysteretic behavior is characterized by the load-displacement curves from static nonrolling vertical loading tests. Using a highly simplified finite element model based solely on tire catalog information and general constructional information, a hysteresis material model is used to simulate the hysteretic load-displacement behavior of farm tires. By choosing appropriate parameters for the hysteresis model, the static nonrolling finite element analyses results correlate very well to the experimental results. The fitted hysteresis material model is then used to simulate the dynamic rolling of a tire dropping off a curb. The bouncing vertical acceleration is of great interest to off-road tires. First, implicit dynamics is used to simulate the rolling using the calibrated hysteresis model. Very good correlations between the simulation results and vehicle test results are obtained. For better off-road rolling performance, the hysteresis model is recalibrated to reduce the vertical acceleration of the tire after the first bounce following the drop-off. The hysteresis model is replicated in explicit dynamics using an Abaqus/Explicit VUMAT subroutine to simulate the dynamic tire rolling behavior. By introducing additional damping and creep dissipation, the vertical acceleration is attenuated in excess of 50% after the first bounce following the drop-off to improve riding comfort. This hysteresis characterization has been shown to give good agreement with test data on nonrolling tests and dynamic drop-off tests. All modeling and solutions were performed using commercially available Abaqus software.Abstract

Schematic of Bergstrom-Boyce hysteresis model.

Displaced shape of the uniaxial tension unit-cube model.

Comparison of force-displacement loops for unit-cube uniaxial tension models using Abaqus/Standard and Abaqus/Explicit.

Displaced shape of the simple shear unit-cube model.

Comparison of force-displacement loops for unit-cube simple shear models using Abaqus/Standard and Abaqus/Explicit.

Test setup for nonrolling test.

Trailer vehicle for drop-off test.

Vertical cyclic loading tire nonrolling test model.

Comparison of 0.1 Hz analysis load-displacement loop with that of test.

Comparison of 5 Hz analysis load-displacement loop with that of test.

Comparison of 10 Hz analysis load-displacement loop with that of test.

Initial and intermediate configurations of tire rolling off a 5 in. step.

Comparison of vertical accelerations between drop-off analysis and drop-off test at 2.4 m∕s line speed.

Comparison of reaction forces between drop-off analysis and drop-off test at 2.4 m∕s line speed.

Comparison of vertical accelerations between drop-off analysis using recalibrated parameters and drop-off test at 2.4 m∕s line speed.

Comparison of reaction forces between drop-off analysis using recalibrated parameters and drop-off test at 2.4 m∕s line speed.

Comparison of 0.1 Hz analysis load-displacement loops with those of nonrolling tests at 83, 160, and 241 kPa inflation pressures.

Initial and intermediate configurations of the large tire rolling off a 5 in. step.

Comparison of vertical accelerations between drop-off analysis using recalibrated parameters and baseline model at 160 kPa inflation pressure.

Comparison of vertical accelerations between drop-off analysis using recalibrated parameters and baseline model at 83 kPa inflation pressure.

Comparison of vertical accelerations between drop-off analysis using recalibrated parameters and baseline model at 241 kPa inflation pressure.

Comparison of force-displacement loops between drop-off analysis using recalibrated parameters and baseline model at 83 kPa inflation pressure.

Comparison of force-displacement loops between drop-off analysis using recalibrated parameters and baseline model at 160 kPa inflation pressure.

Comparison of force-displacement loops between drop-off analysis using recalibrated parameters and baseline model at 241 kPa inflation pressure.