TRACTION LOSS OF A SUSPENDED TIRE ON A SINUSOIDAL ROAD
1984; SAGE Publishing; Issue: 1000 Linguagem: Inglês
ISSN
2169-4052
Autores Tópico(s)Soil Mechanics and Vehicle Dynamics
ResumoIt has been known for some time that automobiles lose a significant percentage of their traction when exposed to a sinusoidal road input, that is, a washboard road, above certain speeds. Similarly, when an automobile is on a four post shaker, it is common practice to use an approximately 10-Hz shaker frequency, and then push the automobile by hand to position it on the shaker. Early studies of a laboratory test with a fixed axle showed that there is significant loss in traction at higher amplitudes or higher frequencies (shorter wavelengths or high speeds), or at a combination of the two. Presented in this paper are the results of a study on the effects of sinusoidal roads on the traction of the right front quarter-car assembly of a 1968 Oldsmobile Toronado using the circular track apparatus at the Pennsylvania Transportation Institute. The results show that as much as 30 percent of the automobile's traction is lost at frequencies of 11 Hz (as compared to a flat track), and that the rate of decay increases rapidly by this frequency. Furthermore, the loss of traction increases for larger input amplitudes; 11 Hz is comparable to a vehicle traveling at 55 mph on a road with roughness at a 7.3-ft wavelength.
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