Abstract

Occupational vehicle drivers are exposed to vibration environment which is known to cause discomfort, annoyance, and health and safety risks. The seated occupant responses to whole-body vibration have been widely investigated along the vertical axis alone. Owing to the comparable magnitudes of vibrations observed in heavy road and off-road vehicles along horizontal axes, there exists a need to investigate the occupant responses to horizontal vibration. Only a few studies have reported seated occupant responses to horizontal vibration, which consider either back unsupported posture or vertical back support. The applicability of the reported data for sitting postures adopted in typical vehicles is thus questionable. Moreover, the influence of the seat height has not yet been addressed. This dissertation research concerns with biodynamic response characterization of the seated human subjects exposed to horizontal vibration through measurements of dynamic interactions between the seated body and the seat pan, and the upper body and the seat backrest in terms of apparent mass and absorbed power.