Development of Omni-directional Injury Criteria for a Pedestrian Dummy for Evaluating Rib Fracture 2009-01-1210
Pedestrian - motor vehicle collisions account for approximately 15% of all traffic fatalities in Europe and the US, and 35% or more in Japan and Asian countries. Several studies have addressed this issue, such as the EEVC study. In the development of the test methods, body region priorities are mainly based on studies of pedestrian collisions with passenger vehicles. However recently, the populations of SUVs and LTVs are increasing in many countries. Pedestrian collision data indicate that thoracic and upper abdominal injuries are also frequent in pedestrian collisions where these kinds of vehicles are involved. However, evaluation methods for pedestrian torso injuries are not currently available.
This paper describes a study for the evaluation of pedestrian thoracic and upper abdominal injuries using the POLAR II pedestrian dummy. Upper abdominal organs mostly injured in pedestrian collisions are within a human’s ribcage, and many of the thorax injuries are associated with rib fractures. Accordingly, only the thoracic responses, especially rib fractures, were considered in this study.
First, the thorax of a human FE model was impacted at various velocities and angles. Rib fractures were investigated and deflections of the thorax in lateral and fore-aft directions were recorded. Based on these results, a method to evaluate rib fractures using the lateral and fore-aft responses, from not only lateral or frontal impacts but also any direction between them, was developed.
From the dummy responses in the condition with which human bodies were injured, injury criteria for the POLAR II dummy were established for lateral and frontal impacts. These results were interpolated using the human FE simulation results. Then a rib fracture evaluation method with the POLAR II dummy for impacts from various directions was established. With these results, the POLAR II can be used as a tool to evaluate pedestrian rib fractures when impacted in the thoracic area.