Accession Number : AD0823500

Title :   PERFORMANCE OF SOILS UNDER TIRE LOADS. REPORT 6. EFFECTS OF TEST TECHNIQUES ON WHEEL PERFORMANCE.

Descriptive Note : Technical rept.,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS

Personal Author(s) : Murphy, Newell R., Jr

Report Date : OCT 1967

Pagination or Media Count : 57

Abstract : 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)

Descriptors :   *TRAFFICABILITY), (*SOILS, (*TIRES, PERFORMANCE(ENGINEERING)), FRICTION, SOIL MECHANICS, SHEAR STRESSES, CLAY, DYNAMOMETERS, SAND, DEFLECTION, MOBILITY, LOADS(FORCES), VEHICLES, MECHANICAL PROPERTIES, TORQUE, PRESSURE, CURVE FITTING.

Subject Categories : Soil Mechanics
      Surface Transportation and Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE