Numerical Investigation of Injury Biomechanics of the Thorax and Lower Extremities Under Different Restraint Systems Using Wayne State University Human Model

Although newer vehicles are equipped with airbags and there is a high percentage of vehicular occupants who are wearing seatbelts, injuries to the thorax and lower extremities accounted for 33% of all occupant injuries. Moreover, when considering the frequency of injuries with a severity on the Abbreviated Injury Scale (AIS) of 3 to 6 (heretofore referred to as AIS 3+), injuries to the chest and lower extremities accounted for a total of approximately 43% of all occupants with these injuries. Consequently, a more detailed study of injury risks to these two body regions is called for. A series of numerical studies has been conducted to simulate a frontal crash using a three-dimensional (3D) finite element (FE) whole body human model representing a 50th percentile male to estimate the injury risks to the thorax and lower extremities. Three different combinations of restraint systems were simulated along with the no restraint condition. Results indicate that injury risks to the thorax were much higher in an unrestrained driver compared to those of a driver restrained by either the airbag only, three-point belt only, or combined airbag and three-point belt condition. On the other hand, injury risks to the lower extremities in occupants without any restraint or airbag only were greater than those restrained by three-point belt only or combined airbag and three-point belt. The combined airbag and three-point belt system simulated in this study showed the lowest injury risks to the thorax and lower extremities.Copyright © 2005 by ASME