VIBRATION TRANSMISSIBILITY OF VARIOUS SEAT OCCUPANTS’ BODY PARTS – A FIELD TEST

VIBRATION TRANSMISSIBILITY OF VARIOUS SEAT OCCUPANTS’ BODY PARTS – A FIELD TEST

D. D. I. Daruis, M. J. M. Nor, B. M. Deros, and M. Hosseini Fouladi

Abstract: Vibration transmissibility from seat to various parts of the body of a number of seat occupants was investigated. The study was carried out in the field using a Malaysian made compact car. Vibration from two types of road and three different vehicle speeds for each road were studied. The effects of three head and back conditions namely head and back supports, back and no head supports and no head and no back supports, were also investigated. Eleven subjects participated in the study. Measurement was done while subject was seated at the front passenger seat. The various body parts measured were right thigh, under the buttock, lumbar, upper back and head (in x-, y- and z-axes). Results show agreement with previous literatures where the median primary resonances were between 4-9 Hz. It was also shown that there were only slight differences with the head and back condition variation except for x- and y-axes for head transmissibility. For both lateral and fore-aft directions, there are large increases of amplitudes when the head and back was not supported as compared to supported back and head conditions. Although it was a field test, coherence values were found to be high (median value of 0.8 to 0.9) for vertical transmissibility however only moderate for fore-aft and horizontal transmissibility (median value 0.7).

Keywords:  seat transmissibility, seat vibration, seat, transmissibility, vibration.

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