A Parametric Study of an Adaptive Load-Limiting Restraint System With Weight Sensing Considerations

The subject study provides an overview of several rear seat restraint configurations, with a focus on the restraint performance of a real-time adaptive (RTA) retractor system. The simulated RTA system assumes the integration of the TCJ Technology into the retractor. The near real-time response and high torque generation capabilities of the TCJ technology are briefly discussed and physical test data are shown in support. Simulations of both a conventional retractor and a 3kN LL retractor are carried out as well. The conventional retractor system is void of any specific energy management, other than the seatbelt stretch itself. Both the 3kN LL and the RTA systems are equipped with energy management functionalities. Simulations of the three restraint configurations are conducted in the MADYMO software with five different ATD models and six different crash pulses. The ATD models range from the HIII 6YO to the HIII 95th percentile male. The vehicle crash pulses originate from the NHTSA database for barrier impacts, with five pulses at the 35-mph severity level and one pulse at the 25-mph severity level. The MADYMO Control System modeling capabilities are relied upon to develop and implement the feedback control system for the RTA model. Seatbelt pay-out amounts and seatbelt pay-out rates are monitored during the simulated crash events. The sensor data are fed real-time into the RTA control system and real-time adaptive retractor seatbelt forces are thus generated. The research initially assumes direct occupant weight sensing is absent and later assesses that the RTA system can indeed function without this third input. A recommended load-limiting performance envelope for the RTA system is specified based on the simulation results. Data interpretation highlights the benefits of an RTA-type system for the full spectrum of modeled occupant sizes and weights, with an understanding that the smaller and more vulnerable occupants (elderly) tend to benefit most when restraint systems are more compliant, and yet able to prevent excessive seatbelt pay-outs for heavier occupants, without any significant detriment in injury numbers across the board. The noted improvements in the 25-mph simulation further bolster the broader benefit aspect, as a greater majority of occupant exposures occur at less than the 35-mph severity.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 22p
  • Monograph Title: 26th International Technical Conference on the Enhanced Safety of Vehicles (ESV): Enabling a Safer Tomorrow

Subject/Index Terms

Filing Info

  • Accession Number: 01760509
  • Record Type: Publication
  • Report/Paper Numbers: 19-0057
  • Files: TRIS, ATRI, USDOT
  • Created Date: Dec 7 2020 3:32PM