Abstract:

The chest injury values of a driver side dummy were optimized in a frontal offset impact test to
heighten the dummy chest point as in the China New Car Assessment Program (C-NCAP). Chest loads and
pelvis loads of a dummy were analyzed. The analyzed results are that the fore-end of driver side seat cushion is
higher and the back-end is lower, which cause the pelvis rebound back too quick and the chest go ahead with a
rush, and the waist belt is draught up. During this course the low-end of chest-frame is compressed, going with
the displacement enlarged. The seat structure was optimized by computer aided engineering (CAE) and sled
test to enhance the rigidity of seat cushion back-end about 50%, with the method of welding the connection steel
wire between the steel wires under the seat cushion. The results show that enhancing the rigidity of the backend
at the seat cushion can heighten about 1 point of C-NCAP assessment when the rigidity of seat cushion is
lower as wish in the frontal offset impact tests.

Key words: vehicle, passive safety, frontal offset impact test, chest displacement, seat cushion rigidity