Seat Belt Buckle Performance in High Energy Wheel-to-Ground Impacts

For more than 20 years, field research and laboratory testing has consistently demonstrated that wearing a seat belt dramatically reduces the risk of occupant death or serious injury in motor vehicle crashes. The injury prevention benefits of seat belts require that they remain fastened during collisions. Federal Motor Vehicle Safety Standards and SAE Recommended Practices set forth seat belt buckle performance requirements to ensure proper buckle performance in accident conditions. Numerous analytical and laboratory studies have investigated buckle inertial properties. While studies have shown that current buckle designs have inertial release thresholds well above conditions believed to occur in real-world crashes, there is limited data characterizing severe wheel to ground impacts.

This study investigates seat belt buckle responses to severe wheel to ground impacts. This is accomplished through the analysis of accelerations during full vehicle drop tests. Amplification of the amount necessary for seat belt buckle inertial release did not occur. These tests also confirm that the magnitudes and durations of the accelerations recorded at the buckle were well below those necessary for inertial release. While no simulation can replicate all field crash scenarios, the acceleration analyses can provide engineers with an effective diagnostic tool for assessing seat buckle performance in realistic high energy crash scenarios.