Vibration Effect Investigation in Baby Car Seats and Automobile Seats

Vibration is both a source of discomfort and a possible risk to human health. There have been numerous studies and knowledge exists regarding the vibrational behavior of vehicle seats on adult human occupants. Children are more and more becoming regular passengers in the vehicle. However, very little knowledge available regarding the vibrational behavior of child safety seats for children. Therefore, the objective of this study was to measure the vibrations in three different baby car seats and to compare these to the vibrations at the interface between the driver and the automobile seat. The test was performed on the National road at the average speed of 70 km/h and acceleration levels were recorded for about 350 Sec (5.83 min). One male driver considered as an adult occupant and a dummy having a mass of 9 kg was representing one year old baby. Four accelerometers were used to measure the vibration. All measured accelerations were relative to the vertical direction. Vibration Analysis Toolset (VATS) was used for time domain analysis. Based on the ISO 2631-1's levels of discomfort, all the baby car seats acceleration levels were between 0.315 - 0.63 m/s² level, which showed that baby car seats considered were little uncomfortable for the baby occupants. The baby car seat 3 comparatively had a lesser exposure to vibration (i.e., lesser VDV value) and better vibration isolation property than other baby car seats.