A Study of Compatibility and Vehicle Front Stiffness Based on Real-World Accidents

The aim of this research was to find vehicle characteristics including stiffness that is effective for compatibility performance. Compatibility is said to be affected by three factors: vehicle mass, geometry and stiffness (1, 2). Of these factors, stiffness has more flexibility at the design stage than vehicle mass and geometry which are limited by the vehicle application. However, the stiffness is assumed to have a conflict issue between the self-protection and the partner-protection (3). In this research, it was analyzed comprehensively how some defined factors such as stiffness, mass, crash stroke and other vehicle characteristics indices relate to each occupant injury rate of the case and its partner vehicle in the real-world accidents. Both “front-to-front” and “front-to-side” crash occupants were covered.

It was found that four vehicle characteristics indices are effective for compatibility performance: toe-board intrusion and maximum vehicle deformation force in offset frontal crash tests (64km/h), and toe-board intrusion and maximum force up to 200 mm deformation in full-lap frontal crash tests (55km/h). Their contribution ratios were quantitatively identified. For each frontal and lateral collision, the vehicle force deformation characteristics were obtained for the vehicles with high and low compatibility from Compatibility Diagram of Self and Partner-protection defined in this research. The analyses are based on the JNCAP test data and 1998-2005 real traffic accident data in Japan. The traffic accident data in Japan utilized in this study are compiled by ITARDA (Institute for Traffic Accident Research and Data Analysis). However, further research with more vehicle types beyond the JNCAP test vehicles and more accident types including single vehicle accidents is required.