In this study, the effect of posture, vibration magnitude and frequency on seat–to–head (STH) and back support–to–head (BTH) transfer functions has been studied under vertical sinusoidal vibration. Twelve healthy male subjects participated in experimental work to measure vertical vibration transmitted to the occupants' heads in three representative postures (erect, vertical backrest and forward lean on table) under three magnitudes of vibration (0.4, 0.8 and 1.2 m/s² r.m.s.) in frequency range 1 to 20 Hz. From collected data sets, the effects of vibration magnitude, vibration frequency and postures on STH and BTH transmissibility and phase were measured over the prescribed frequency range. The result suggested that inclusion of all possible variables in optimal design of vehicle seat, suspension and comfort analysis would improve the design and analysis. The comparison of experimental and model response reveals that both models matched with mean experimental data sets most closely and the models provide the best description of the biodynamic response of seated human subjects under vertical whole body vibration.
Keywords: human vibration, seated posture, seat to head transmissibility, low frequency vibration, biodynamic modelling, biodynamics, back support to head transfer functions, vertical vibration, sinusoidal vibration, optimal design, seat design, vehicle seating, suspension design, comfort analysis