Abstract: The lower torso assembly of the Hybrid III (HIII) crash dummy adopts a one-piece vinyl skin/urethane foam design with a shape resembling the hip and thighs of a seated occupant. Although a ball-and-socket joint is used to connect the femur and the pelvis, the fixed shape flesh design has essentially constrained the rotational freedom of the hip joint. A more human-body-like lower torso design is proposed and used to modify a nonlinear finite element model of HIII dummy. Impact responses of the modified dummy model are compared with those of the original dummy model under different loading conditions in frontal impact. The results indicate that the modified dummy model is more human-like in its pelvis structure and more suitable for safety analysis of reclining seat. An anti-submarine countermeasure for reclining posture is proposed in the CAE environment. The sled test is performed to verify the concept of the anti-submarining countermeasure. The proposed countermeasures can well eliminate the submarining under frontal impact loading of 48 km/h, with which all the other injury parameters require in FMVSS 208 do not exceed their respective tolerance levels.

Key words: Crash test, Hybrid III crash dummy, Reclining seat, Submarining