REAR IMPACT HEAD DISPLACEMENT REDUCTION THROUGH THE APPLICATION OF STRAIN RATE HARDENING CUSHIONING MATERIALS

摘要

A head restraint for a seat includes a core support structure supporting a dual rate cushioning foam. The dual rate cushioning foam includes a dilatant material that changes from a first compression rate providing a first stiffness to a second compression rate providing a second stiffness in response to a strain rate in the dilatant material rising above a pre-defined limit. The first compression rate at the first stiffness provides a softer feel to the occupant for normal operation of the vehicle. The second compression rate at the second stiffness provides a stiffer resistance to resist the sudden rearward movement of the occupant's head in the event of a sudden rear impact.