Title: Strain rate dependency in paratransit bus rollover

Authors: Bronislaw Gepner; Michal Gleba; Sungmoon Jung; Jerry W. Wekezer

Addresses: FAMU-FSU College of Engineering, Department of Civil and Environmental Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA ' FAMU-FSU College of Engineering, Department of Civil and Environmental Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA ' FAMU-FSU College of Engineering, Department of Civil and Environmental Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA ' FAMU-FSU College of Engineering, Department of Civil and Environmental Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046, USA

Abstract: This paper examines the effect of structural steel strain rate dependency on the outcome of the FDOT/ECE-R66 bus rollover test. Bending and impact tests were performed on structural tubing in order to evaluate strain rate dependency parameters. Several mesh densities were used to investigate the influence of mesh size on the final outcome of the analysis. Two strain rate dependency formulations, Cowper-Symonds and Johnson-Cook, were calibrated and then implemented in the finite element analysis of a paratransit bus rollover. Unlike strain rate effect on other types of impact such as the frontal crash, the results show that the strain rate has no significant effect on the FDOT/ECE-R66 rollover test. Therefore, the current approach used by researchers investigating bus rollovers, to validate finite element models based on quasi-static experiments, is well-grounded and the strain rate dependent effects may be ignored for the global deformation response in the ECE-R66 bus rollover.

Keywords: bus safety; finite element analysis; strain rate dependency; paratransit buses; bus rollover; UN ECE-R66; heavy vehicles; structural steel; bending tests; impact tests; structural tubing; deformation response.

DOI: 10.1504/IJHVS.2016.074624

International Journal of Heavy Vehicle Systems, 2016 Vol.23 No.1, pp.1 - 20

Received: 03 Nov 2014
Accepted: 17 Jul 2015
Published online: 09 Feb 2016 *

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