Biomechanical analysis of head-neck force in hybrid III dummy during inverted vertical drops.

The hybrid III dummy has been used extensively for crash testing. The comparison between the cadaver and dummy data provides the biofidelic nature of dummy head-neck system to predict cervical spine injury as a function of applied force. The existing dummy data are limited to a lower drop height up to 0.5 m. The present study quantified the head-neck biomechanical response of the dummy up to a drop height of 1.20 m. At 0.15 m, the head force was 5740 N and 5695 N at the upper neck and 4231 N at the lower neck. At 0.6 m, the head force was 13,000 N and 12,000 N at the upper neck and 8900 N at the lower neck. At 1.2 m, the calculated head force was 19,500 N and 18,600 N at the upper neck and 13,500 N at the lower neck. The present results closely match with data of previous studies. The data indicated that the hybrid III system transmits about 70 to 75% of the applied force from the head or upper neck to the lower neck area. In contrast, the cadaver studies showed for drops from 0.9 to 1.5 m, about 20 to 30% of the applied force was transmitted from the head to the lower neck. The comparison demonstrates the capability of the Hybrid III dummy head-neck force response to realistically predict injury and also the need for comparing the dummy's response to the human head neck force data for injury.