End-to-End Seat Virtual Prototyping from Manufacturing to Performances

Today, in the transportation industry, two antagonist phenomena lead the OEMs to change radically their design processes.

On the one hand, the technical constraints which influence the design of the vehicles and their components are changing and increasing in numbers. For instance, the new environmental regulations are requiring a diminution of CO2 emission, which can be translated as a specification for the use of lighter materials to replace the ones traditionnally used. For a seat frame, it means replacing (part of) the steel by composites or structural foam. Environmental regulations impose as well the use of materials which can be recycled. To fullfil that requirement, the polyurethane foams should be replaced by natural fibers coming from soy or coconut. In both cases, these environmental regulations lead to the use of materials whose properties are less identified, for which the industry has less background, and which will require as a consequence,
some research and innovation.

On the other hand, economical constraints are pushing to the reduction of design cycles costs and duration, so that it is already difficult to maintain the current processes and almost impossible to introduce a part of research. 

The conclusion is that the current design process has to change so that the costs savings will enable this innovation. Today, it relies for part on simulation (mostly for safety performances) and for part on physical testing on prototypes, for the domains whose physics are less straightforward.

This paper shows an illustration on an industrial seat of how this design can be handled fully virtually, covering the processes of manufacturing of the components and the performances evaluation of the final assembly. 

The cover sewing and wrapping processes were simulated and led to the change of the design to avoid some
craftsmanship issues. Then, using the updated and assembled virtual seat, the positioning of dummies was simulated to measure some quantities such as H-Point, angles, and backset distance. The crash test dummies were positioned as well and the sled tests were performed for the different regulations. Mechanical and thermal comfort were evaluated through the use of validated human models and the use of the Berkeley model. Finally the seat life cycle was explored through the inclusion of material fatigue properties.