Hisakazu Harada

DEVELOPMENT OF HIGH PERFORMANCE SEAT CUSHION PAD FOR VEHICLE VIBRATION ABSORPTION

While driving, accelerations and vibrations may affect the human body. When the resonance frequency of the seat interacts with that of the human body, large vertical vibrations cause discomfort and tiredness. In order to reduce and absorb vibration from vehicles, the performance of the seat cushion pad was investigated. The viscoelastic properties of the polyurethane pad were analysed. The vibrations transmitted to the human body of volunteer subjects included sensations of vertical motions at 2-4Hz, pressure on the stomach at 4-8Hz, and rough, intense jolting of the thighs at 8Hz and above. The development of urethane materials with high vibration absorption is described and the use of seat pads with these materials reduced vibration absorption and improved ride comfort. For the covering abstract see ITRD E121867.