Influence of road roughness wavelengths on bus passengers’ oscillatory comfort

Abstract

This paper analyses the effect of the waviness parameter w on the oscillatory comfort of bus passengers for one road in good condition. The analysis is carried out by a validated nonlinear oscillatory 16 degrees of freedom (DOF) bus model defined in the software Matlab/Simulink and procedure from ISO 2631/1997 standard. The root-mean-square (RMS) values of the weighted vertical accelerations from the passengers’ seats increase with the increase in the parameter w. On the other hand, the RMS values of the weighted vertical accelerations from bus floor decreased with the increase in the parameter w. The best oscillatory comfort has a passenger in the middle part of the bus, and the worst has a passenger in the rear part of the bus. The intensities of the vertical accelerations from the bus floor are mainly concentrated into two frequency ranges, 0 ÷ 2.5 Hz and 5 ÷ 10 Hz. The passenger seats are dampened with vertical vibrations above 4 Hz. For the narrow range w = 1.5 ÷ 2.3, nominal value of the waviness parameter (w = 2) is sufficiently precise in assessment of the bus passengers’ oscillatory comfort.