Title: Predictive vehicle ride discomfort model based on in-situ Stevens power law parameters

Authors: Anand N. Thite

Addresses: Faculty of Technology, Design and Environment, Oxford Brookes University, Wheatley, Oxford – OX33 1HX, UK

Abstract: The current dynamic ride comfort mathematical models do not use Maxwell arrangement of vehicle suspension occurring due to top mount and the discomfort weightings used are based on the shaker table tests which ignore the influence of vehicle dynamics, for example the effect of seat cushion. A refined integrated vehicle-occupant, 10 degrees of freedom model that includes top mounts is developed to estimate the occupant response to given harmonic input. The dynamic responses are combined with experimentally obtained in-situ discomfort indices for a car that incorporates the effects of features such as seat cushion. The Stevens power law parameters are estimated and compared with previous studies; the perception model is then used to predict discomfort index as a function of frequency. The influence of the relative stiffness of the top mount and suspension damping on the resonance frequencies is discussed. The acceleration in wheel hop mode can be ~3 times larger than that when top mount is not included. The influence of resonance frequencies suggests importance of not just using frequency average discomfort index while optimising suspension and seat parameters.

Keywords: ride comfort; four post rig; Stevens power law; Maxwell model; discomfort index; top mount; vehicle suspension.

DOI: 10.1504/IJVNV.2017.089530

International Journal of Vehicle Noise and Vibration, 2017 Vol.13 No.3/4, pp.326 - 349

Available online: 23 Jan 2018 *

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