Chest injury criterion:​ an update of the equivalent deflection (DEQ)

Trosseille, Xavier; Song, Eric; Petitjean, Audrey

Affiliations

¹LAB PSA Peugeot-Citroën Renault, France

Abstract

The rodpot chest deflection measured on the HIII dummy does not discriminate the contributions of the belt and the airbag in crashes. The risks associated to the deflection being different for these two kinds of devices, the assessment of the risk with the rodpot deflection is erroneous for combined restraining systems. Combined restraints known to be efficient in protecting the thorax are consequently penalized. In 2003, the equivalent deflection (Deq) criterion based on the HIII rodpot deflection and the shoulder belt force and applicable to belt, airbag as well as combined restraints was proposed. It has since been evaluated and reviewed by users providing some requests for improvements such as the sensitivity to changes in the pelvic restraint. The objective of this study was to update the Deq criterion to address as much as possible the feedbacks from the users and better predict chest injuries.

New data from HIII 50th percentile tests performed under conditions more representative of the loading encountered with current restraints were collected from the literature. It allowed to better define the relationship between the shoulder load and the deflection caused by the belt. The Deq formulation was updated in order to increase its sensitivity, particularly to airbag loading. Additional paired dummy and PMHS (Post-Mortem Human Subject) tests allowed increasing the size of the sample used to validate the principle of the Deq criterion. The validation of the new formulation was also conducted through simulations with human and HIII models. Then, the biomechanical data were reprocessed with currently recommended statistical methods (based on survival analysis) to build a thoracic injury risk curve for the HIII 50th dummy. Finally, a thoracic injury risk curve was provided for the HIII 5th female.

This paper provides the set of data (dummy, PMHS and numerical simulations) used to define and validate the criterion, as well as the equations of the thoracic injury risk curves as a function of the Deq resulting from their processing. The feedbacks from the users as well as the related improvements of the criterion are presented. The effect of the rodpot deflection and the upper shoulder belt force on the Deq is described.

The aim of the Deq criterion is to improve the thoracic protection in frontal crash in the short term, therefore using the currently used HIII dummy. As such, this criterion enhances the prediction of the risk associated with combined restraints compared to the HIII rodpot deflection. However, it does not fully compensate the error introduced by the use of the rodpot deflection.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv23/23ESV-000342.pdf

Cited Works (14)

Year	Entry
2009	Forman J, Lopez-Valdes F, Lessley D, Kindig M, Kent R, Ridella S, Bostrom O. Rear seat occupant safety: an investigation of a progressive force-limiting, pretensioning 3-point belt system using adult PMHS in frontal sled tests. Stapp Car Crash J. 2009;53:49-74. SAE 2009-22-0002.
1971	Kroell CK, Schneider DC, Nahum AM. Impact tolerance and response of the human thorax. In: Proceedings of the 15th Stapp Car Crash Conference. November 17-19, 1971; Coronado, CA. Warrendale, PA: Society of Automotive Engineers:84-134. SAE 710851.
2005	Laituri TR, Prasad P, Sullivan K, Frankstein M, Thomas RS. Derivation and evaluation of a provisional, age-dependent, AIS3+ thoracic risk curve for belted adults in frontal impacts. In: Proceedings of the SAE World Congress & Exhibition. April 11-14, 2005; Detroit, MI. Warrendale, PA: Society of Automotive Engineers. SAE 2005-01-0297.
2005	Gennarelli TA, Wodzin E, eds. The Abbreviated Injury Scale 2005. Barrington, IL: Association for the Advancement of Automotive Medicine (AAAM); 2005.
1974	Kroell CK, Schneider DC, Nahum AM. Impact tolerance and response of the human thorax II. In: Proceedings of the 18th Stapp Car Crash Conference. December 4-5, 1974; Ann Arbor, MI. Warrendale, PA: Society of Automotive Engineers:383-457. SAE 741187.
2006	Forman J, Lessley D, Shaw CG, Evans J, Kent R, Rouhana SW, Prasad P. Thoracic response of belted PMHS, the Hybrid III, and the THOR-NT mid-sized male surrogates in low-speed, frontal crashes. Stapp Car Crash J. 2006;50:191-215. SAE 2006-22-0009.
2005	Lebarbé M, Potier P, Baudrit P, Petit P, Trosseille X, Vallancien G. Thoracic injury investigation using PMHS in frontal airbag out-of-position situations. Stapp Car Crash J. 2005;49:323-342. SAE 2005-22-0015.
2003	Mertz HJ, Irwin AL, Prasad P. Biomechanical and scaling bases for frontal and side impact injury assessment reference values. Stapp Car Crash J. 2003;47:155-188. SAE 2003-22-0009.
2011	Song E, Lecuyer E, Trosseille X. Development of injury criteria for frontal impact using a human body FE model. In: Proceedings of the 22nd International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 13-16, 2011; Washington, DC.
1998	Foret-Bruno J-Y, Trosseille X, Le Coz J-Y, Bendjellal F, Steyer C, Phalempin T, Villeforceix D, Dandres P, Got C. Thoracic injury risk in frontal car crashes with occupant restrained with belt load limiter. In: Proceedings of the 42nd Stapp Car Crash Conference. November 2-4, 1998; Tempa, AZ. Warrendale, PA: Society of Automotive Engineers:331-352. SAE 983166.
2001	Kent R, Bolton J, Crandall J, Prasad P, Nusholtz G, Mertz H, Kallieris D. Restrained Hybrid III dummy-based criteria for thoracic hard-tissue injury prediction. In: Proceedings of the 2001 International IRCOBI Conference on the Biomechanics of Impact. October 10-12, 2001; Isle of Man, UK.
2003	Kent R, Lessley D, Shaw G, Crandall J. The utility of Hybrid III and THOR chest deflection for discriminating between standard and force-limiting belt systems. Stapp Car Crash J. 2003;47:267-297. SAE 2003-22-0013.
2003	Petitjean A, Baudrit P, Trosseille X. Thoracic injury criterion for frontal crash applicable to all restraint systems. Stapp Car Crash J. 2003;47:323-348. SAE 2003-22-0015.
2011	Petitjean A, Trosseille X. Statistical simulations to evaluate the methods of the construction of injury risk curves. Stapp Car Crash J. 2011;55:411-440.

Cited By (2)

Year	Entry
2013	Cerdan D, Zeitouni R, Adalian C. Frontal impact protection: application of an upgraded chest injury criterion - the equivalent deflection (Deq). In: Proceedings of the 23rd International Technical Conference on the Enhanced Safety of Vehicles (ESV). May 27-30, 2013; Seoul, South Korea.
2014	Sunnevång C, Hynd D, Carroll J, Dahlgren M. Comparison of the THORAX demonstrator and HIII sensitivity to crash severity and occupant restraint variation. In: Proceedings of the 2014 International IRCOBI Conference on the Biomechanics of Injury. September 10-12, 2014; Berlin, Germany.377-388.