Title: Quarter car model stress analysis for terrain/road profile ratings

Authors: J. Gavin Howe, Jeffrey P. Chrstos, R. Wade Allen, Thomas T. Myers, Dongchan Lee, Chi-Ying Liang, David J. Gorsich, Alexander A. Reid

Addresses: 4115 Ashmore Road, Columbus, OH 43220, USA. ' 1321 Broadview Ave, Columbus, OH 43212, USA. ' 13766 S. Hawthorne Blvd., Hawthorne, CA 90250, USA. ' 13766 S. Hawthorne Blvd., Hawthorne, CA 90250, USA. ' 13766 S. Hawthorne Blvd., Hawthorne, CA 90250, USA. ' 13766 S. Hawthorne Blvd., Hawthorne, CA 90250, USA. ' US Army RDECOM, National Automotive Center, 6501 E. 11 Mile Road, AMSRD-TAR-N MS: 157, Warren, MI 48397-5000, USA. ' US Army RDECOM, National Automotive Center, 6501 E. 11 Mile Road, AMSRD-TAR-N MS: 157, Warren, MI 48397-5000, USA

Abstract: The US Army currently uses the root mean square of elevation (RMSE) and power spectral density (PSD) to characterise road/terrain roughness for ground vehicle durability assessment. This paper describes research aimed toward improving these measures. One potential method is running a relatively simple, yet vehicle class specific model over a given terrain and using predicted vehicle response(s) to characterise the terrain. A precedent for this concept is the International Roughness Index (IRI), used in the highway industry. The IRI consists of a simple tyre model and quarter car vehicle model run at a specified speed to estimate suspension velocity over a road profile. Another method of estimating road roughness is fatigue analysis. In this study, a generic specimen was subjected to the quarter car suspension forces. The stresses developed were used to make a fatigue life cycle prediction. This paper presents the key concepts and results from this analysis.

Keywords: international roughness index; IRI; fatigue life cycle prediction; power spectral density; PSD; repetitions of failure; root mean square of elevation; RMSE; speed roughness index; SRI; terrain rating; road roughness; terrain roughness; vehicle suspension forces; stress analysis.

DOI: 10.1504/IJVD.2004.005359

International Journal of Vehicle Design, 2004 Vol.36 No.2/3, pp.248 - 269

Published online: 28 Sep 2004 *

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