SEDL / STP / STP884-EB / STP34601S

Road Roughness Effects on Vehicle Dynamics

Wambold, JC
Professor of mechanical engineering and director, Automotive Research Program, Pennsylvania Transportation Institute, Pennsylvania State University, University Park, PA

Pages: 18    Published: Jan 1985

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Abstract

This paper is based on the Kummer Lecture presented in June 1983 to ASTM Committee E-17 on Traveled Surface Characteristics. It is intended to be a tutorial on the effects of road roughness on vehicle dynamics and is aimed primarily at those members of the highway community who generally are not versed in vehicle dynamics.

The paper first presents both a quarter-car and a half-car simulation, from which the various effects of road roughness can be used as input into the simulation to obtain various measures from the dynamic model. In particular, the acceleration of the sprung mass can be used, along with a standard such as the ride quality standard of the International Organization for Standardization (ISO), to establish the effects of a rough road on the ride quality of a vehicle. In a similar manner, the effects of a rough road can be applied to determine the energy loss by looking at the forces on the shock absorbers, while the loads transmitted back down through the tire to the pavement can also be investigated. Another application of the theoretical quarter-car model is that it can be used to determine the effects of vehicle dynamics on a road roughness meter, such as the Mays meter or the Portland Cement Association (PCA) meter. Finally, a quarter-truck model is presented to show the effects of roughness on a truck model, as opposed to the car model presented earlier.