Abstract
Vibration transmitted from the cushion to the human head can affect riding comfort and even induce motion sickness during the vertical excitation. Although seat-to-head transmissibility has been investigated using a rigid seat, only biodynamic properties of seated occupant were considered and influence of the seating dynamics was neglected. In this study, the in-line and cross-axis seat-to-head transmissibilities of 14 seated occupants were investigated on an elastic seat with the vertical excitation (1–15 Hz) of three different excitation magnitudes (0.2, 0.4, 0.8 m/s2 r.m.s.). The influence of contacting with or without the backrest on the transmissibilities was also analysed. The primary peak frequencies approximately at 4 Hz of the seat-to-head transmissibilities significantly decreased when increasing the excitation magnitude. When contacting with a backrest, the higher primary peak frequencies were observed in seat-to-head transmissibilities for both the vertical in-line and the fore-and-aft cross-axis directions, compared to the measurements without contacting to the backrest. Seat-to-head transmissibilities measured with an elastic seat in this study differs markedly from those tested on a rigid seat in previous studies. This highlights the necessity of further investigation of the influences of dynamic body-seat interactions on seat-to-head transmissibilities, in order to enhance the insight into riding comfort.