Development of a Methodology forSimulating Seat Back InteractionUsing Realistic Body Contours

Seat comfort is driven in part by the fit between the sitter and seat. Traditional anthropometric data provide little information about the size and shape of the torso that can be used for backrest design. This report introduces a methodology for using three-dimensional computer models of the human torso based on a statistical analysis of body shapes for conducting automated fit assessments. Surface scan data from 296 men and 417 women in a seated posture were analyzed to create a body shape model that can be adjusted to a range of postures spanning those typical of vehicle occupants. A parameterized finite-element model of an auto seat surface was created, along with custom software that generates body models and postures them in the seat. A simple simulation technique was developed to rapidly assess the fit of the torso relative to the seat back. Further refinement of the method will allow prediction of seat surface pressure distribution, which may be usefully related to subjective assessment of seat fit.