PERFORMANCE OF SOILS UNDER TIRE LOADS. REPORT 6. EFFECTS OF TEST TECHNIQUES ON WHEEL PERFORMANCE.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
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A study was made of the effects of various testing techniques on the performance of pneumatic tires operating in an air-dried desert sand and a nearly saturated fat clay. Tests employing both controlled-slip and controlled-pull techniques were conducted with single-wheel dynamometer carriages. The results are presented in the form of graphs with emphasis placed upon the pull-slip and torque-slip relations. For the conditions tested, wheel performance was found to be independent of testing techniques, with one exception consistent differences were noted between the results of programmed-increasing- and programmed-decreasing-slip tests. However, this disagreement occurred only for a narrow range of slip approximately -10 to 10. Careful and complete analysis of a dynamic test system must be made to determine the forces that actually represent the wheel performance. A brief analysis of the horizontal forces acting on the test dynamometers is given to emphasize this point, particularly with regard to differences between pull-slip and drawbar pull-slip relations. It is shown that because of the inability always to attain a stable condition in controlled-pull tests, controlled-slip tests are better for defining pull-slip relations. Author
- Soil Mechanics
- Surface Transportation and Equipment