A Study of Vibration Transmission on Seated Person in passenger Vehicle

摘要

In land vehicles such as cars, vibration from the surface of the road or ground is transferred through the tyres, body of the car, and seat to the occupants of the vehicle. This type of vibration, in which the entire body of a person or object experiences the vibrational forces is known as whole-body vibration. The effect of whole-body vibration on a person can be detrimental depending on the duration and severity of exposure. Due to the potential discomfort, health and safety concerns whole-body vibration may cause, this research aims to study the transmission of whole-body vibration for better understanding of its effects on the human passengers. This paper discusses the measurement and assessment of whole-body vibration experienced by a passenger in three models of vehicle, each from a different car segment (compact, sedan and MPV). Vibrations in the x, y and z-axes at seat pan and backrest and near the feet of the driver of the three vehicles was measured while they were driven at four different constants speeds of 40, 60, 90 and 110 km/h. Seat effective amplitude transmissibility of the vehicle seat pans were evaluated. Frequency weighted acceleration root-mean-square values and vibration dose values were calculated and evaluated according to the two standards of ISO 2631-1 and BS 6841 with respect to discomfort and health. The findings correlated to discomfort and health from both the ISO 2631-1 standard and BS 6841 standard were compared. Power spectral densities were calculated to determine the dominant frequencies in the vibration measured. The results showed that vibration generally increases with speed at medium to high velocities but reduces with speed at low to medium velocities. It was also found that for the vehicles evaluated, there was a lack of vibration attenuation on the seat. Furthermore, vehicle class does not necessarily impact vibration magnitudes in a significant way. Lastly, the BS 6841 standard underestimates discomfort as opposed to the I