TIRE PERFORMANCE IN SOIL
Corina Sandu
Robert E . Hord Jr . Professor & Associate Department Head for Graduate Studies
Dr . Corina Sandu and her recently graduated PhD student , Dr . Rui He , have been investigating the performance of tires on soil for the past four years . The work was funded by the Engineer Research and Development Center . Their study has enhanced the understanding of tire tractive performance on soil and advanced the development of terramechanics and tire model parameterization methods through experimental tests .
The tests ( static tire deflection , static tire-soil , soil properties , and dynamic tire-soil ) resulted in data that can be used in off-road traction dynamics and terramechanics modeling . The 225 / 60R16 97S Uniroyal Standard Reference Test Tire was used . The study included the quantification and / or measurement of soil properties of the test soil , pre-traffic soil condition , the pressure distribution in the tire contact patch , tire off-road tractive performance , and post-traffic soil compaction .
The influence of operational parameters ( tire inflation pressure , normal load , slip ratio , initial soil compaction ), or the number of passes on the measurement data of tire performance parameters or soil response parameters was analyzed . New methods of the rolling radius estimation for a tire on soft soil and of the 3-D rut reconstruction were developed . A multi-pass effect phenomenon , not discussed in available existing literature , was discovered .
The test data was fed into optimization programs for the parameterization of the original Bekker ’ s pressure-sinkage model , a modified Bekker ’ s model which accounts for the slip sinkage effect , the Magic Formula tire model ( adapted to account for the combined influence of tire inflation pressure and initial soil compaction on the tire tractive performance and validated by the test data ), and a bulk density estimation model .
38 RESEARCH • VIRGINIA TECH MECHANICAL ENGINEERING ANNUAL REPORT • 2019-2020