This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Optimized Ride-Down Rate Control in Frontal Impact and its Application in the Energy Management of Occupant Restraint System
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 08, 2013 by SAE International in United States
Annotation ability available
This paper presents an analytic approach to determining the optimized ride-down rate-the relative amount of occupant kinetic energy dissipated in vehicle structure deformation, and attempts to address the question of how the desired ride-down rate could be realized in vehicle design. In this paper the ride-down rate is divided by a critical ride-down rate value into two areas: a positive-effect-area where an increase of ride-down rate will lead to a decrease in the occupant injury level, and a negative-effect-area where an increase in ride-down rate could lead to an increase in the occupant injury level. The critical ride-down rate is found to occur at around 50% for a sedan class vehicle frontal crash into a rigid barrier at 56 km/h of NCAP test setup. The critical ride-down rate can also be estimated with various constraints such as occupant injury levels, vehicle categories and crash modes. Ride-down rate measurements from NCAP tests showed satisfactory agreement with the analytical calculation results from the ride-down rate models.
This paper also presents a ride-down rate control approach in terms of coupling design between the occupant restraint system and dynamic structural behavior. Impact event timing control and occupant travel space compatibility with respect to the compartment are found to be critical in ride-down rate control. A theoretical analysis on the relationship between the ride-down rate, impact timing, and the occupant relative displacement/structure crush ratio is presented and compared with the measurements from NCAP tests. Occupant relative displacement with respect to the vehicle is treated as an engineering variable that could control the ride-down rate in a vehicle safety design.
Setting the capacity levels for each sub-restraint system in the beginning of system integration is a critical starting step, because it would reduce costly late engineering changes. An approach to energy management of an occupant restraint system is finally given based on the optimized ride-down rate control concept. Optimized ride-down rate makes it possible to configure a desired occupant energy curve by a trapezoid in displacement domain, which could be used to distribute the occupant kinetic energy into sub-restraint systems such as airbag, safety belt and steering column.
The interactions between safely belt, airbag and steering wheel have been discussed in publications. This paper isolates each sub-system from the complex interaction by using the trapezoid analysis method in the displacement domain, which sets a series of minimum performance criterion for each sub-restraint system. This procedure of breaking down the performance criterion for sub-restraint systems is finally validated by inputting a set of sub-restraint system parameters into a numerical model. The dynamic response from this numerical model correlated very well with the desired trapezoid energy curve in the displacement domain, from which the input parameters were generated.
CitationQiu, S., Li, H., Zhang, J., Ma, Y. et al., "Optimized Ride-Down Rate Control in Frontal Impact and its Application in the Energy Management of Occupant Restraint System," SAE Technical Paper 2013-01-0760, 2013, https://doi.org/10.4271/2013-01-0760.
- Grimes , W. D. , and Lee , F. D. The Effect of Crush Pulse Shape on Occupant Simulations SAE Technical Paper 2000-01-0460 2000 10.4271/2000-01-0460
- Motozawa , Y. , and Kamei , T. A New Concept for Occupant Deceleration Control in a Crash SAE Technical Paper 2000-01-0881 2000 10.4271/2000-01-0881
- Wu , J. , Bilkhu , S. , and Nusholtz , G. An Impact Pulse-Restraint Energy Relationship and Its Application SAE Technical Paper 2003-01-0505 2003 10.4271/2003-01-0505
- Cao , J. , Koda M. and Law , S. Vehicle Pulse Shape Optimization to Improve Occupant Response in Front Impact SAE Technical Paper 2004-01-1625 2004 10.4271/2004-01-1625
- Witteman , W. J. , and Kirens , R. F. C. The Necessity of an Adaptive Vehicle Structure to Optimize Deceleration Pulses for different Crash Velocities 17 th ESV, Netherlands, June 4-7 2001
- Mark , S. Effect of Frontal Crash Pulse Variations on Occupant Injuries 18 th ESV, Japan, May 19-22 2003
- Varat , M. S. , and Husher , S. E. Crash pulse Modeling for Vehicle Safety Research 18 th ESV, Japan, May 19-22 2003
- Katoh , H. , and Nakahama , R. A Study on the Ridedown Evaluation Proceeding 9th International Conference on Experimental Safely Vehicles Japan November 1 4 1982
- Evans , N. , Furton , L. , and Cok , D. Occupant Energy Management Technique for Restrain System analysis and Design- Theory and Validation SAE Technical Paper 922082 1992 10.4271/922082
- Bonello , K. Occupant energy Management Technique for Restaurant System Analysis and Design - Understanding the Physics of the System SAE Technical Paper 922083 1992 10.4271/922083
- Huang , M. , Laya , J. , and Loo , M. A Study on Ride-Down Efficiency and Occupant Responses in High Speed Crash Tests SAE Technical Paper 950656 1995 10.4271/950656
- Vehicle Crashworthiness and Occupant Protection American Iron and Steel Institute Michigan 2004
- Huang M. , Vehicle Crash Mechanics CRC Press Boca Raton 978-0-8493-0104-9 2002
- NHTSA Vehicle Crash Test Database http://www.nhtsa.gov/Research/Databases+and+Software 2012
- Nancy , C. E. , Lisa , M. F. , and David , A. C. Occupant Energy Management Technique for Restrain System analysis and Design -Theory and Validation SAE Technical Paper 922082 1992 10.4271/922082
- Kenneth , J. B. Occupant Energy Management Technique for Restraint System Analysis and Design - Understanding the Physics of the System SAE Technical Paper 922083 1992 10.4271/922083
- Byron , B. The Coming Revolution in Airbag Technology Proceeding of 16th International Technical Conference on the Enhanced Safety of Vehicles Canada May 31 June 4 1998
- Farid , B. , Gilbert W. , Christian S. et al. The Combination Of a New Air Bag Technology With a Belt Load Limiter Proceeding of 16th International Technical Conference on the Enhanced Safety of Vehicles Canada May 31 June 4 1998
- Koichi , K. , Yoshihiko M. , and Makoto N. Study Of Test Procedure To Evaluate Airbag Deployment Force Proceeding of 16th International Technical Conference on the Enhanced Safety of Vehicles Canada May 31 June 4 1998