Assessment of the impact of sub-components on the dynamic response of a coupled human body/automotive seat system

Abstract

Automotive seats are complex structures composed of several sub-components and designed to provide the best driving comfort to the occupant. From a mechanical point of view, this amounts to ensuring both optimal body support and vibration isolation. However, considering the multiple interactions between these sub-components and the seated human body, it still remains difficult to identify design trends to a priori improve the seat dynamic performances. To handle these issues, a test campaign is first conducted, according to current industrial protocols, to characterize the impact of each seat sub-component on the cushion vertical transmissibility. Then, a multi-body human/seat system is implemented and validated, to assess the influence of all the parameters related to the seat but also to the human body, using global sensitivity analysis methods. It is shown that the foam and cover composing the cushion essentially control the dynamic performances of the seat. However, the variability associated to the internal dynamics of the human body must be taken into account, as it strongly influences the maximum amplitude of the transmissibility of the human/seat system and therefore the vibrational comfort.