Rear-End Impacts – Part 2: Sled Pulse Effect on Front-Seat Occupant Responses
2022-01-1039
03/29/2022
- Event
- Content
- This study was conducted to assess the effects of differing rear impact pulse characteristics on restraint performance, front-seat occupant kinematics, biomechanical responses, and seat yielding. Five rear sled tests were conducted at 40 km/h using a modern seat. The sled buck was representative of a mid-sized driver environment in a generic sport utility vehicle. The peak acceleration, acceleration shape and duration were varied. Three of the pulses were selected based on published information and two were calculated to assess the effects of long and short initial acceleration rate using a trapezoidal characteristic shape. The angle at maximum seatback rearward deformation varied from 26 to 47 degrees. It was lowest in Pulse 1 which simulates an 80 km/h car-to-car rear impact. The seatback plastic deformation was greater in the pulse with a long initial acceleration rate, Pulse 4, than in the short acceleration rate, Pulse 5 (28 degrees v 22 degrees). Coincidingly, the longitudinal head displacement was greater in the Pulse 4. There was limited relative motion between the occupant and the seatback. The vertical pelvis displacement was less than 5 cm, irrespective of pulse characteristics. The head, chest and pelvis acceleration peak and timing varied depending on the pulse. For example, the peak pelvis acceleration was lowest in Pulse 1 and greatest in Pulse 4. The biomechanical responses were all well below injury assessment reference values. The occupant acceleration data was combined with the rotational data to determine the effective restraint stiffness and develop a spring-mass damper model. The model will be used to help understand the effects of pulse characteristics on predicted chest acceleration for future research.
- Citation
- Parenteau, C., White, S., and Burnett, R., "Rear-End Impacts – Part 2: Sled Pulse Effect on Front-Seat Occupant Responses ," SAE Technical Paper 2022-01-1039, 2022, .