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item Way, Thomas - Tom

Submitted to: Biosystems Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2003
Publication Date: 3/23/2004
Citation: Way, T.R., Kishimoto, T. 2004. Interface pressures of a tractor drive tyre on structured and loose soils. Biosystems Engineering. 87(3):375-386.

Interpretive Summary: As reduced tillage farming systems are becoming increasingly important, the proportion of farm vehicle traffic occurring on untilled soils is increasing. Soil compaction and the performance of farm vehicle tires are affected by contact pressures of tires on soil. Contact pressures of a tractor tire were measured as the tire ran on an untilled clay soil, a tilled sandy loam, and a tilled clay loam soil. The pressures were most uniform on the tilled sandy loam, least uniform on the untilled clay, and intermediate on the tilled clay loam. On the untilled soil, the pressures on the tire lugs were considerably greater than those on the tread region between lugs. This information is expected to be useful to manufacturers of agricultural tires and tractors, and researchers, in improving the performance of tractors and other agricultural vehicles.

Technical Abstract: An 18.4R38 radial-ply tractor drive tire was operated at 10% travel reduction, at three correctly inflated combinations of dynamic load and inflation pressures on a structured clay soil and at another combination of load and inflation pressure on a loose sandy loam and a loose clay loam soil. Soil-tire interface pressures on the face of one lug and on an undertread region between two lugs were measured, and were used in estimating the tire footprint area for the operating tire. On the structured clay soil, the interface pressures on the lug face were substantially greater than tire inflation pressure and those on the undertread were considerably less than inflation pressure. On the loose sandy loam and the loose clay loam, some interface pressures on the lug face exceeded inflation pressure by only a small amount and others were a small amount less than inflation pressure, while undertread pressures were less than inflation pressure. Tire footprint areas on the structured clay soil were nearly equal for the three correctly inflated load and inflation pressure combinations. The footprint area on the loose sandy loam was 10% greater, and that on the loose clay loam was 4% greater, than the average of the three footprint areas on the structured clay soil.