In order to increase confidence in the reliability and accuracy of the linear random vibration theory in predicting vehicular behavior, an experiment was performed with a four-wheeled model vehicle having an independent suspension system. The vehicle has three degrees of freedom (vertical translation, pitch, and roll) and was made to operate at different speeds on a simulated road bed with randomly distributed surface roughness. Using linear random vibration theory, equations giving the power spectral density of each degree of freedom about the vehicle's center of gravity were derived as a function of the power spectral density of the four wheels' vertical displacement. Numerical and experimental techniques enabled a direct comparison to be made between theoretical predictions and experimental results. The linear random vibration theory gave reliable predictions at higher speeds and on rougher terrain. Deliberate, asymmetrical loading of the model vehicle had little effect on the reliability of linear random vibration theory predictions. A comparison between results of linear random vibration theory and a numerical-nonlinear technique showed the superiority of the former in predicting experimental results, with a relatively small computing time requirement.

  • Availability:
  • Supplemental Notes:
    • Presented at SAE Off-Highway Vehicle Meeting and Exposition, Milwaukee, Wisconsin, 11-14 September 1978.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Chu, M L
    • Doyle, G R
  • Publication Date: 1978

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00399031
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: SAE 780789, HS-025 599U
  • Files: HSL, USDOT
  • Created Date: Aug 31 1985 12:00AM