Van der Westhuizen, Sarel FrancoisEls, Pieter Schalk2016-03-152016-03-152015-02Van Der Westhuizen, SF & Schalk Els, P 2015, 'Comparison of different gas models to calculate the spring force of a hydropneumatic suspension', Journal of Terramechanics, vol. 57, pp. 41-59.0022-4898 (print)1879-1204 (online)10.1016/j.jterra.2014.11.002http://hdl.handle.net/2263/51830When developing any simulation model some compromise must be made between computational efficiency and the accuracy of the model. This study compares the performance of three ideal gas (IG) law variations (IG with the energy equation (EE), isothermal and adiabatic), and two real gas approaches (Benedict Webb Rubin (BWR) equation with and without the EE) to model the spring force of a hydropneumatic suspension. These models are compared with experimental data obtained from laboratory tests on a single hydropneumatic suspension unit. Both the BWR and IG models with the EE offer a significant improvement in correlation compared to the models without the EE. The real gas BWR approach offers a small improvement over the IG approach under the test conditions. The best (BWR with EE) and worst (IG isothermal) models are then used to model the spring forces in a full vehicle model of a 4 × 4 Sports Utility vehicle (SUV). The data is again compared with experimental results and the BWR model with the EE correlates significantly better than the IG isothermal model. It is thus concluded that the inclusion of the EE will yield significantly better results and it should only be omitted if the parameters investigated are not sensitive to errors in the spring model.en© 2014 ISTVS. Published by Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Journal of Terramechanics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Terramechanics, vol. 57, pp. 41-59, 2015. doi : 10.1016/j.jterra.2014.11.002.Vehicle simulationHydropneumatic suspensionSuspension modellingSpring modellingGas modellingModel verificationReal gasIdeal gas (IG)Energy equation (EE)Benedict Webb Rubin (BWR)Engineering, built environment and information technology articles SDG-09SDG-09: Industry, innovation and infrastructureEngineering, built environment and information technology articles SDG-11SDG-11: Sustainable cities and communitiesEngineering, built environment and information technology articles SDG-12SDG-12: Responsible consumption and productionPostprint Article