Evaluation of the SID Dummy and TTI Injury Criterion for Side impact Testing

The NHTSA's side impact dummy (SID) was evaluated against what is known of the side impact response of the human chest and responses were compared with data on Hybrid III frontal and EURQSID side impact characteristics. The SID dummy lacks a human-like chest deflection response which is crucial to the injury indicating capability of a dummy, it has a 9.8 kg near-side rib mass which is approximately an order of magnitude greater than that of the human, and it develops impact forces that are nearly three times higher than the recommended human chest response. It possesses characteristics primarily of an inertial device. The thoracic trauma index (TTI) was evaluated as an indicator of side impact injury risk, and design trends and optimized padding characteristics identified with the SID and TTI were compared with those from the Hybrid III dummy and viscous or compression injury criteria. TTI is an acceleration-based criterion which averages the maximum near-side rib and spinal acceleration irrespective of differences in times of occurrence, it is determined in the first milliseconds of impact, much earlier than human injuries can occur, and it is insensitive to the total kinetic energy of impact, so that TTI may indicate a safe exposure when an understanding of the full events of impact clearly indicate a significant injury risk. The SID dummy and TTI injury criterion were found unsuitable for side impact injury evaluation.